A DIY Power Pulse Controller
This device uses a built in pulse width modulated signal generator circuit for triggering a power MOSFET.
The circuit is great for controlling the power delivered to a device such as a fan, LED's or even transformers and coils. By adjusting the pulse width you can easily control the speed of a fan without sacrificing torque.
This particular transistor, the IRF740 is rated up to 400V and can switch around 10A which makes it quite useful for power switching in inductive loads. The circuit will run from a 6V - 12V DC supply and the output can be made as 'open collector' for higher voltage switching.
Don't fancy building it yourself? Check out our range of advanced pulse generators
This circuit diagram shows the load (coil, motor etc) connected to the same supply as the rest of the circuit for simplicity. If you need to switch a higher voltage, the +ve connector of the load can simply be connected to an external supply.
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Parts List
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| IC1 | LM555 |
| IC2 | LM393 |
| R1 | 10k |
| R2 | 10k |
| R3 | 2.2k |
| R4 | 10k |
| VR1 | 1M |
| VR2 | 10k |
| C1 | 47nF |
| T1 | IRF740 |
If the circuit is to be used with inductive loads a small capacitor should be connected across the load These are often already fitted on small DC motors. An additional component such as a varistor or 'freewheel diode' is also recommended if the pulse generator is driving high voltage flyback transformers like ignition coils.
The two potentiometers VR1 and VR2 are used for controlling the frequency and duty cycle of the output. VR1 adjusts the rate at which C1 is charged for modifying frequency, while VR2 acts as a potential divider allowing a specific voltage to be put on the inverting input of IC2. This voltage is used to control the pulse width of the output. The output duty cycle or pulse width of the device can also be controlled by an external voltage such as a microcontrollers or analog signal. The analog voltage source can simply be connected to the inverting input instead of the output from VR2.
Features and Specifications
- Input 9 to 15V, 10A
- Power Output - 9 to 15V DC Square wave
- Open collector output allows for use of separate voltage source for pulses.
- Independent frequency and pulse width / duty cycle controls
- Frequency adjustable between 0Hz and 125kHz (C1 must be changed for full range)
- Pulse width fully adjustable between 0% and 100%
Example applications
- (PWM) Motor Speed Control
Pulse Width Modulation (PWM) is used to accurately control the speed of DC motors. The pulse frequency can be adjusted to match your motor for performance or reducing noise. The speed of the motor can be adjusted using the preset on the board, or it can be attached another variable voltage source such as the analog output from a microcontrollers or similar device. - Dimming or Flashing of LED's and Light bulbs
This module can be used to smoothly dim lights or make them flash at regular intervals. The brightness is adjusted by a pulse width modulated signal which can be set to and inaudible frequency - Tone Generator for small or large speakers
This circuit generates an adjustable square wave signal that is powerful enough to drive anything from piezoelectric sounders to large bass speakers. The frequency range can be adjusted between sub bass and ultrasonic levels. - Solenoid or Relay Pulsing
Simple variable rate on/off function for driving relays, or moving solenoids with repeated strokes. - Coil Pulsing
Drive coils and electromagnets with regular current pulses of up to 10 Amps. Ideal for magnetic launchers and many other pulsed coil experiments. At higher pulse frequencies the PWM control can be used to adjust the average field strength of a coil. - SMA Wire Driver
The variable pulse generator can be used as an adjustable current source for powering muscle wire (shape memory alloy SMA wire). By using a medium frequency setting, the PWM control can be used to adjust the average current flowing through the muscle wires giving precise control over the movement. At low frequencies muscle wire can be pulsed for repeated movements.
We have a few of these pulse generators designed for use with high voltage transformers which available on the cyber circuits page. These are high quality, ready made on a PCB including a large heatsink and fan, overload protection, and back e.m.f. inductive protection. Theses devices are quite resilient and are ideal for hobbyists and experimenting due to the wide range of potential uses and durability for handling varied loads. If you have random transformers or are making your own coils, these power pulse modulators are ideal for testing and driving them.
Don't fancy building it yourself? Buy our PWM-OCXI now!
The information provided here can not be guaranteed as accurate or correct. Always check with an alternate source before following any suggestions made here.
What kind of diode(part) is the D1 at the A DIY Power Pulse Controller ?
I am looking to use this circut to drive for paralel ignition coils.
Thanx
Some Ignition Coils ideal for use with this circuit have also been added to the science store.
Now i have a Dimmer and flasher in 1 circuit.
Looking forward to playing ( experimenting ) with this.
Powered it up with a pp3 battery and it seems to run fine from that. 12 Volts later :-).
What is a wheel diode?. Never heard the expression before..
Great stuff, many thanks..
The diode is used as a path for the current when the transistor is switched off. If you think of the current in the load as carrying momentum, when the transistor is off the current can continue through a diode. With out a current path the voltage accross the load can rise quite high which may damage components in the circuit.
Update from Earlier post..
Found Ignition coil and 12Volt Supply.( wifes car lol ).
Connected it to the Pulse controller and blew the LM393, oops.Not good..Connected 4.7nf capacitor across the load ( ignition coil ) and tried again.Much Better. Coil produces sparks from 5Volts. At 10 volts the spark becomes and arc..Noted the IRF740 will warm up quite quickly if the coil is not tuned to well. With 12 Volts input I could easily run a jacobs ladder.
The best Ignition Coil driver I have tried.
Its particualy susceptible when you are getting a high output from the ignition coil and you are making and breaking arcs. This is because breking of the arc causes HV spikes in the circuit which can damage sensitive parts like the 393 or 555. A capaictor helps, but a surge protector such as a varistor might be needed at high output levels.
This video is of a Jacobs Ladder I made with this pulse controller and a HV Spark Coil
This video is of arcs from a sphere on top of an pulse controller and a HV Spark Coil
Oops another LM393 bites the dust.Running a 40 watt bulb as a plasma ball is ok till the negative croc clip drops off.Must buy better sticky tape..Awaiting LM393`s..
I wonder if smoking LM393`s is bad for my health..
I'd add some surge supression if your gonna be stressing your circuit. Something like these Transient Voltage Supressors should help. You normally place them between a sensitive rail (like a signal input or output from 393) and ground.
It can sometimes help to just put one in parralel with your battery or DC supply so that if the voltage rises too high it will be shorted out. You will probably need a current limiting resistor too though if you do it like that.
I made a small modification to you circuit over the weekend.Added an ampmeter so I can see what effect the tuning has on the current drawn,this should help a little.I am suprised at just how much the current will rise.
I will fit a pair of Inductors later to see what help they are, if any..
Many thanks for the help and tips..
My goal is the 12Volt tesla. I picked up 22 used 2n3055`s cheap, Looking out for heatsink now for 9?.. I am trying to Quit smoking LM393`s, honest Guv..
I got lucky finding my mega heatsink in a local electronics shop. I have a couple of double T0-3 type heatsinks around somewhere. Let me know if you want them, and you can have em both for £5, or whatever international shiping costs if you are not in the UK.
I've also seen some allmost identical ones on ebay here
I used nine 2n3055's on the Power Pulse Generatorbecause it filled up the heatsink, but I think that its overkill really. It only ever gets warm when driving 4 ignition coils, but having nine leaves plenty of room for adding bigger or unknown loads like electromagnets.
I fitted the following. 2 Inductors, 1 to each input of the coil / coils. 2x1n4007, 1 to the power supply between the coil and lm393, and 1 on the negative of the lm393, Dont really know if it helps any but i have blown up nothing today. Tried driving 2 coils and found no problems, even when the spark is over 1 inch.
I can get a good 10mm arc with .5 amps. Jacobs ladder is no problem with 10 Volts into 2 coils.
***********************************************
Heatsinks for the 2n3055`s. At this time i am using CPU heatsinks. These work really well and have the added bonus of a fan. To use, drill the holes for the connections through the base into the channel for the retaining clip. Push the wire through the holes and then solder. Two self tapping screws to secure.Does that make sense?..
A fun day, thankyou again for all the help and advice..I may take you up on the offer of the heatsinks, I`ll see how i get on first..
I have looked at the heatsink link, these would be ideal. I would like to take you up on your offer..
Thanks..
I sent you an email about the 2n3055 heatsinks to the address you provided.
kilidjian@ciudad.com.ar
Tkanks !!!!!
Fitted the 2n3055`s to the heatsinks, but not working yet.Need to look into that.
thnx
The simples way to put the components together yourself may be to use a prototyping board, or breadboard.
I want to drive a pair of ignition coils then a Tesla
PLEASE recommend how to put Varistor or other safety features to protect the PWM
I have used two inductors made from biro cases on the ign. coil inputs in the past with the single sign. gen and ign. coils but Iam not sure this is enough.. A good tip is to keep checking each completed section of the circuit as you build it with a small loudspeaker or piezo -electric beeper( scraped microwave oven?)
I got lucky...FINE site
neat time I come around it will be as a member, I hope
There is no way of getting a frequency range of 0-125 MHz @ 10A with any circuit like this. The impedance in the MHz range is just too high for delivering that kind of current without any special power conversion.
These values are pretty rough because the pot allows you to adjust a good range from each capacitor.
The frequency range depends upon the capcitor value of C1, but the full range would be about 0-125kHz
I have tired a couple of PCB programs but im not having much luck. I have Eagle v4, seems nice, PCB123 gives me a headache.
Thanks in advance.
You may need to wire an IGBT using thick cable rather than PCB tracks.
Great site RMCybernetics
I'm thinking about placing the diode between the coil and the load(+).
1. If I use an electronic coil from a car, what Diode do you recommend to use that can take the voltage of the coil. will a 1n1198 do the job?
I've been told that a car coil can output over 40K volts. dont know about amps though.
any help would be greatly appreciated.
The output voltage of an ignition coil depends on the specific model used, but I would say that 20kV is about average from a good 12V square wave driver.
The output current is only small and it is also pulsed. Semiconductor devices often have a rating for continuous current and a seperate rating for pulse or surge current.
If the coil steps up V from 12 to 20,000, we can assume that the current will be stepped down by the same amount (~1667 times). If the input current is 5A, then the output current will be about 2.9mA.
These values are pretty rough because of the pulsed nature and variablity of the system, but they should give you an idea of the minimum ratings for any component used on the output.
Maybe the BY8418 (22kV 100mA) would be suitable.
Hunter Any succes with your project?
I'm thinking to add another coil, but trying to be able to control it individually from the other. is it possible with this circuit.
thanks for all your help
If you want to independantly control a seperate coil with a different frequency or pulse width, you will need a whole extra circuit.
I am tryin to get the coil to spark at a different time.
the ony thing holding me back is the fact that i am using an electronic ignition from a 92 honda an it has 3 wires coming out
I know that one comes from the trigger ond another goes to ig. switch. and im guessing the other is for 12v straight as well.
Ill try using two cables(12v +) and one for +pulsing from circuit. I will also ground the coil. hope this works alright.
thanks again
A varistor provides protection when it is placed between a pin of a voltage sensitive device and ground. The value of the varistor is chosen to be slightly lower than the max voltage of your device. With this setup, if the voltage on your protected pin rises too high, the varistor will activate and short the pin to ground. This can obviously have other concequences which would depend upon your specific application.
A varistor can be used in another way for protecting transistors. If it is placed between the collector/drain and the base/gate it will cause the transistor to switch on when the voltage rises too high. This then prevents over voltage between the collecter and emitter (drain and source).
A varistor will have will take a finite amount of time to activate. If the transients are rising too fast, the varistor is rather useless.
A zener diode can be used in a similar way. If one is connected in reverse bias mode between the pin you need to protect and ground, the zener will limit the voltage on that pin to the voltage ratin of the zener. These also have a finite response time.
Another method is to construct a snubber circuit. These come in many flavours, but are generally some combination of a resistor and capacitor. Thse can be made to limit the voltage rise, or they can limit the rate of rise of the transient. They can be placed in the DC part of your circuit, or they can be placed on the transformer output.
The design of switch mode power supplies (this is essentially what you are making) can be rather tricky, especially when the freqency is variable and the voltage difference between input and output is large. There will be a section on transient protection in the learn electronics section at some time, but I have not got a eta for its completion yet.
Thanks
I've not tried this, so you may need to experiment a little.
Is a variable resistor the same as a trimpot,
Is the R1 R2 R3 and R4 1% metal 5% carbon or wirewound
A trimpot is a type of variable resistor.
The tollerence (%) of the components indicates how much the actual value you get (resistance, capacitance, etc) might differ from the manufacturers stated value. The type is not too important, these were used for this project.
The 3rd terminal of VR1 is left unconnected.
If you use the same supply for the circuit and the transistor/load, the maxiumum is 12V @ 10A (120W)if the transistor is kept cool. If you are not using 100% of the duty the transistor will handle slightly more power.
Another question same topic
If I got a 12v signal pulsing at 10 times a second could I delay that pulse, but still pulse at 10 times a second. And stay in sync(or same percentage of delay) if the 12v input pulse was to go up to 50 a second or would i need a different device?
Thank You
I would just buy a thrower kit but this seems a little more fun and reliable.
thanks, I know this seems odd
I tried this circuit as a speed controller but no show, the dc motor still go at the same rate of speed. no matter how much I tweak the pots high or low.
I'm lost here please help
For anyone wondering how to calculate frequency of the circuit.... (The value of VR1 being whatever you adjust it to)
Frequency = 1.44 / ( (R1+VR1+VR1) * C)
= 1.44 / ( (10k+VR1+VR1) * 0.000000047)
Pete's f = 1.44 / ( (10k+54k) * 0.000000047)
= 1.44 / 0.003008
= 478.7234 Hz
Q: Can this circuit run on 6 Volts or can it be modified to be happy with 6 Volts only?
There's no need to order in advance. There will be quite a few available, and if you register your details we will email you when they go on sale.
Make sure that the valuse of R2 and R4 are the same. Some resistors have a large tollerence value which means that there could be a difference of 20% of the stated value between your resistors.
A small reduction in the value of R2 will help tip the pulse width towards the lower end. Alternativley you could increase the value of R4.
The IRF740 will switch a 5V load no problems when the circuit is used in 'open collector mode'.
for independant duty cycle but common freq??
I have not yet sent out any newletter because there has been some delays in getting them made. The kit versions are available now in the Cyber Circuits section. If you want a ready made one, you can back order them and I will make them to order. The newsletter will go out when I've got a batch of ready made ones available.
hootsnboots:
You are exactly right. The duty cycle part works by simply comparing the oscilating voltage to a voltage you set with VR2.
Just go to the cyber circuits page and use the 'back order' button to add the item to your shopping basket. It works in the exact same way as buying any other products the button is just different. Once you complete the order I will get one made and shipped asap.
I intend to use the circuit in a similar, high voltage research type project and would be happy to share my findings with the list.
I'm wondering whether you have any recommendations for PCB design software? It would have to be something that's fairly easy for the likes of me to use.
Many thanks ZS
They provide all the features of this circuit and include extra features such as transient voltage spike protection and indicator.
These devices make an ideal compact yet powerful adjstable power supply or pulse controller. One of these circuits will help you with a huge variety of science and electronic projects. Get yours here.
using a tv you can make your very own ossiliscope by simple disconnecting the vertical defelctor and using that coil as an imput signal.
this is showing no signal and the vertical can clearly be seen.
I was looking at your small ignition and liked what I saw but I believe I am living in a place far away from you to make it impractical to want to buy and get sent one of such coils, so I think I'd rather ask from which scrap equipment can one get such small ignition coils?
Also how does one determine the polarity of ignition coils when they are not indicated on the coils?
Again, I saw a flyback for sale on the same page, I have similar flybacks for projects I'd like to undertake, but how does one determine between the leads; which is primary, secondary and feedback coils leads when there is hardly any indication on the flybacks?
Thanks and keep up the good work.
BDSD.
The wiring is represented in the diagram here. The pins marked GND are connected together inside the casing of the ignition coil. Finding the polarity of the coils can be done with an inductace meter between the output and an input pin. The pin with the lowest inductance is the GND pin.
I tested the flyback you mentioned by simply connecting a Power Pulse Modulator to pairs of input pins and measured the output. By process of elimination two of the input pins were found to create a good output when being driven by the 12V pulses.
What Inductance meter would you recommend?
Also what do you use to measure those very high voltages? What are the normal voltages one can expect to get from 12V Bosch ignition and flyback coils, for example.
I would also like to have your opinion on whether one can use PCB mounted DC-DC converters as shown here, (http://www.hitekpower.com/pcbmountdc.htm), for example, thereby eliminating bulky ignition or flybacks if one's design is not very high current or power?
Best regards.
The Atlas LCR is pretty handy for measuring inductance, capacitance and resistance.
I use a Brandenburg high voltage meter which is basically a big voltage divider and a panel voltmeter.
To measure the output of an ignition coil I use a rectifier and capacitor so can measure a DC voltage. It's typically 20 - 30 kV from a big 12V SLA battery and a coil driver.
Those DC-DC converters are handy for low power and voltage but they are not good for things like Jacobs ladders and Tesla coils like ignition coils are.
By the way, do you have good high voltage capacitors (>=3000V) for sale? If so what's their cost? if not where can one get some at good retails prices?
Thanks,
The MOSFET used is rated to a maximum of 400V so you could also use it to switch a HV source.
This looks like it could be useful for driving automotive fuel injectors in an "extra injector(s)" setup (I.E. to add more fuel only when need as in turbo boost mode activated by a boost pressure switch). Do you think so?
Driving an ignition coil without any load on the output may cause very large spikes. The PWM-OC10A will indicate when the back emf is too large. The simplest way to reduce back emf from an ignition coil would be to load the output (i.e. place a capacitor or resistor between the output of the coil and GND). Alternatively you can place a capacitor across the two input terminals of the ignition coil. The larger the capacitance of the capacitor, the larger the snubbing effect will be. This type of snubber is dissipative and therefore reduces the efficiency of your system.
Thanks for this grat project!
I'm just wondering if that LM555 could be replaced by the ordinary NE555. Because the former one is quite absent at my location?
I've been toying around with the idea of building this controller since I came across this site a few months back, and now think that I may have a valid project for it.
However, I wanted to seek out some advice as to whether or not this particular pulse controller is suitable to drive high (approx 250mW, 3v, 150mA) output laser diodes. If not in its native form, do you guys think that it would be feasible to change the component values to be more suited to these types of laser diodes?
Thanks for your input!
i did the following to protect the circuit.
1. 1n4007 to lm393
2. 10nf@1kv cap also included across D1
3. a small cap and a MOV across the input of the ignition coil
i dont know if it is enough but i haven't fried any 393 to now :)
do you have any other suggestion that i can protect the lm393?
Another way is to place a reverse biased zener diode or MOV between the 393's input and ground.
You could also use the spare amp in the 393 IC as a buffer for increasing its output impedance.
Most of these methods may have some small effect on performance such as increased switching time caused by extra capacitance.
It's also worth noting that using a battery as the supply means that your ground connection has limited current sinking abilities therefore it's not always going to stay at 0V when the circuit is active.
If your fan is stuck on full speed it means that either there is a short circuit which bypasses the transistor, or that the oscillator is not oscillating and is stuck high causing the transistor to be switched on permanently.
Use a MOV (varistor) pull any voltage spikes down to ground.
You probably shouldn't apply 15V directly to the circuit as it is shown because there are no resistor protecting the ICs. You would need to place a resistor between the ICs V+ and the +15V to keep the voltage within the manufacturers ratings. 15V is within the rated input range for both ICs (555 = 16V, 393 = 36V), but it would not be good practice to run them so close to the limits without some sort of current limiting resistor.
Once again, thanks a bunch for all your help :)
Lifespan will depend on your load. Most MOSFETs will do if they are rated for more than the voltage and current you will be using.
mark,
See the ignition coil driver for protection methods
you will need less than 235nF to get higher frequencies. 235nF will give a range of about 1Hz - 600Hz.
You can also increase the frequency by reducing the value of R1.
I'm building my own coil driver using 2 IRF 530 (100V/17A) driving 2 antipararell coils. I,m using a commercial signal generator to drive the IRF:s (through a 180 ohm resistor) And I have enough power (12v/20A) But.. The circuit only draws 0.5-0.7 Amps and the output voltage is roughly 15-20kV. I expected more. Any suggestions anyone?
What voltage does your input signal reach?, It typically needs to reach 10V to switch a MOSFET on fully but you can sometimes get away with voltages as low as 6V.
(Edited by RMCybernetics)
(PS. I deleted the specs you posted as they took too much space on the page)
My induction coils can't create sparks at inaudiable freq. so i can't make audio modulated spark? Please help, it's for my school project.
PS. This site is the best!
You can still audio modulate the spark but you will always have the sound of drive signal. The drive signal should be as high as possible because it will only allow for accurate modulation by frequency's which are half or lower than it.
** a 1.5KE18CA transcient voltage suppressor diode: SHOULD it be across the load, or between pin 1 of the LN393 (output) and ground, or both?
** a capacitor across the load - WHAT value (nF, Volts) would you recommend?
Finally do you use a fat cable from ground to source of the IRF740? It is going to handle a lot of amps?
Many many thanks - Thomas
The datasheet tells you it can. The circuit here with a 393 allows the pulse width to be varied independently of frequency and it will co from 0-100% just from varying one pot. A 555 on its own can not do anything like this.
Thomas,
1.5KE18CA (MOV) would be ok on the output of the 393 like you suggest, but if you place it across the load it might heat up and be destroyed. It would also reduce the efficiency of the circuit.
This is because every time a spike goes above 18V (which will be almost every pulse if the ignition coil is not heavily loaded) all the power meant for the coil will go through the MOV for that instant. If you want a MOV across the coil it should be rated for hundreds of volts so it just clips the top of the highest spikes so they are within the voltage range of your transistor.
Any capacitor across the load should be rated for at least 1kV. The capacitance value would depend on the frequency you operate at. Higher frequency, smaller capacitance. You will need to experiment to find a suitable value. you should also place a resistor in series with this capacitor.
Yes, all power carrying cables should be thick.
Also, how would you test for best capacitor to connect across the load? I have heard that ignition coils usually operate best around 300-1000 Hz, so should I just put in a cap that starts conducting around 10 kHz?
Would you have any ignition coils that work well with this circuit for sale? My ignition coils always give pathetic sparks with either this circuit or the 2N3055 one. Many thanks!
The cap and resistor combination used for a snubber is usually chosen to be the largest capacitance you can use with acceptable losses in efficiency of your circuit.
We are currentl out of stock, but we should have some available soon. Check the high voltage surplus page
I made an oscillator with NE555 and when I
connected ne555 pin3 to lm393p pin3, and other ( pot, v+,v-), voltage on output pin 1 and gnd was 0. I connected all properly. What do You think?
Maximum clamping voltage is the highest voltage that you can expect the MOV to keep between its terminals. If this value is 200V then you would not expect to see any voltages over 200V in your circuit (as long as it is used correctly).
The minimum breakdown voltage is the lowest voltage at which you can expect the device to begin to activate. If this value is 200V then your normal operating conditions must not reach this value.
CrazyMadMan,
Not exactly, but for this circuit it will not matter.
Pin 3 of the 555 outputs a square wave, there is no point in feeding that into the comparator and that is why pin 3 is not used in this circuit. If you have a 555 and a 393 why not build this circuit?
NE555 driver, but I want to make a new, just like that one on this site.
also, what kind of capacitor is C1? is it electrolytic, mylar, ceramic..etc?
this site is really helpful! :D
Start with a low frequency, measure the signal on the gate pin (pin 1). This should be square and at a voltage just below your supply. If its not, remove the IRF740 and set the point which was connected to the gate pin. If it isn't square, then your circuit is wrong somewhere an you will have to just recheck your wiring. if it is square until you put the transistor in then there's possible something wrong with the transistor or the way you wired it.
Thomas,
This is happening because more than the rated current is passing through the device. I doesn't matter how big your heatsink is if you allow too much current to flow. When this occurred did it stop making sound (at the frequency of your drive circuit)? If so, this means the mosfet or other component was damaged by a voltage spike which caused it to permanently latch on therefore allowing the full current to flow through and melt it. See the ignition coil driver page for info on voltage spikes. Sure, I'll try out one of those xformers, I'll send u a couple of HV caps and diodes in return if you like. email us for the address. Cheers
-60 nF 3000V cap (18 3.3 nF 3000V caps in parallel - I had a lot of these!) with a 10K resistor (1W) in series,
-a MOV (200V)
-one neon (Maplin RX70, I assume 0.8 mA since for 220V needs 270k resistor) in serie with a 1K resistor
**basically the three items described for the ignition coil driver.
-a fourth neon ((Maplin BK53H, "built in resistance for 220V")
The first neon (Maplin RX70) lights up. The second neon (BK53H) does NOT light up... am very confused now
I am using a 9V NiH 200mAh battery for this - using a PSU 16V 4 A max fried my IRF740 yesterday
It should not be so low. You must have an error in your circuit but you will have to figure it out yourself. 4V is too low. 10V is a typical value for switching a MOSFET.
Thomas,
The resistor values normally used for the neons are chosen so that they can be lit constantly from the applied voltage source. In this case they only light briefly and we also use them to dissipate some energy. This is why the resistance value is significantly lower. If the voltage of the spike is high a larger current can flow through the neon and therefore more energy is dissipated as light and heat. The second neon will not light because the other snubbing devices are preventing the voltage from rising high enough to power the neon through its resistor.
Shipped the flyback to you today BTW
and if i use a bigger fet vds = 600v then can my input voltage 12 be upgraded to 24+
Yes fortunatley the IRF740 is avalanche rated, meaning it can tollerate such a breakdown if it is only temporoary and within certian limits. Unfortunatly driving an ignition coil with a variable frequency and little or no load on the output will produce lots of back EMF. Imagine the flow of energy in the circuit as if it is a wave. It flows into the primary coil and then from there into the secondary coil via a changing magnetic field. As this energy reaches the output terminal of the coil it sees a huge change in impedance (low in the metal coil to very high in the air). A change in impeadence always causes reflections of waves. This means the energy wave is reflected back into the coil and eventually back to your transistor.
You either need to absorb/dissipate this energy before it hits the transistor, or you need to allow the wave to flow out of the coils output. Once an arc is formed there is a low impedance and energy is not reflected much, but before it forms the air has a huge impedance and causes lots of reflection.
If you are not concerned so much with varying the frequency or voltage then you can use some sort of self resonant or even mechanical oscilator.
tomu,
Square, it will distort and become rounded at higher frequencies.
No. The FET does not effect the input voltage you use. The voltage appled must not exceed that of the comonents ratings. Obviosly the 400V of this mosfet is fine, but the 555 and 393 have lower tollerence.
I recently bought a motor speed controller using a LM555. After completing the kit, it ran the included motor just fine, but when I connected my own DC motor, it would not move at all. At first test, nothing happened at first but then there was a burning smell and a pop. The LM555 was hot, so I thought that was why it wouldn't move that load. Is that the reason or is it because my motor draws too many amps? (sorry i don't know the specs right now, but i will test the motor tomorrow and find the amps). I have attached a picture of the speed controller and the motor which I wish to drive.
Its getting hot because too much current is flowing through it. You can reduce the current by either lowering your supply voltage or increasing the resistance of the circuit. Insert a resistor (about 100 ohms) between the power supply and the IC's power pin.
Chris,
If the motor is physically larger then yes it is likley to have overloaded the circuit. Our PWM circuit will work with large motors.
thankyou for taking the time to answer my question although some people abuse the privilage by asking questions that could be answered by googling lol thankyou great site by the way.
I can't give you a direct replacement, you will need to search yourself. There are potentially hundreds that will work. It just needs to be a low offset comparator for use with a single voltage supply.
Chris,
Your picture will only be accepted if it is a jpeg (.jpg) and less than 200kB in size. The device mentioned will drive motors up to 10 amps.
Yeah sorry I forgot about size. I will convert the image sometime today and upload it. The motor which I mentioned draws 1.35 amps @ 7.2 volts. You mentioned that the power pulse modulator will output up to 10 Amps of current, so can I assume that the circuit can run this motor?
Thanks for your help.
is it possible to use another device stead of lm393 for example a simple comparator in electronic workbench(for simulation)?
thanks alot for the quick reply
bnzd123@yahoo.co.uk
I hoped I might use this circuit for driving another step down transformer to give about 3v at 15 amps max output to a resistance wire cutter.
Do you see any problem with this idea and would I need to protect the output of your pwm circuit? Thanks Graham
What kind of Capacitor should be use as snubbers ?
How to know the volt value for the ceramic/multi layer type ?
thanks
Snubber capacitors should be multilayer or something that can handle a litle power.
how should i protect this circuit from lighting/thunder if i connect it to a fence (sort of electric fence)
pls help. can i just connect earth to the circuit ground ? or at groud of the coil ? with 1 better ?
You would need to set up a lightening rod that would take the strikes instead of the fence.
If you are making an electric fence, the circuit needs have its GND connected to an earth rod anyway.
2. Yes, the filtering works in both directions. You don't need to connect it backwards. Connect the NST to 'load', and mains input to 'line'.
many thanks
The pots should be the values shown then adjusted to give what you want.
Thanks!
-James
Thanks, great site btw!
The power input connections of the second circuit would be linked to the output connections of the first.
Unknownjarg,
No
I am busy building a Marx Impulse Generator and struggling to locate the pins of my Flyback Transformer.plz help!ZTFK82003A
ic7667 n channel mosfet driver for ic2 ?
my 555 is running at 98hz with the 7667
and it shows on the scope running well
but when fed into a power mosfet rated at
1200v 30amps , i get nothing ?
why is this ?
im stumped
any suggestions
thankyou !
No, you can use a MOSFET driver after the 393. The 393 is needed to perform the PWM.
traveler,
Yes, Place them in parallel. THe disadvantage is that the wave becomes less square with each one you add.
i need to run a coil for flamethrowers. my truck is a diesel so i need a pulse controller. i have the ability to build this, but im clueless to the language. what do i need to do to build one (in idiot language lol) i need a 12V source to pulse as fast as possible. please help me! lol
thanks!
jeff
On the 555 timer, reset (pin4) is not connected to anything in your circuit? why is this? I believe that the reset on a 555 is active high so shouldnt it be tied to gnd? Also, what about the control voltage (pin5) or can both of these be left unconnected without affecting opperability. I have built a circuit similar to this one using a 555 timer and 741 op-amp comparator and in order for it to work, it was necessary for pin 4 to be high and a .01uf capacitor be placed between pin 5 and ground.
All these years of elec engineering and I never really messed around with 555's at all....
Voltage range for pulse generator, and min. and max. voltage for output across IRF740?
Does it depend on voltage level of pulse generator?
thanks a mill!
rah2son
thanks a mill
rah2son
You can get up to 2MHz from some 555's but you would need a different circuit. At that frequency you would also need a high speed comparator that works faster than the 393.
The voltage you can switch just depends on the output transistor used. The IRF740 used here is rated for 400V. To apply a higher voltage you would connect the + terminal of the load to your higher voltage source.
Chase_Easy,
The orientation of the pots here just determines which direction you would turn them for increasing or decreasing the respective parameter so you can use them either way around. Yes that pin is left unused.
but my question is i installed my cell in my 1985 chevy pickup i got pretty good production,man i was just wondering would i get more production with voltage or frequency i think voltage.
thanks a mill
Increase the voltage or decrease the resistance. I = V/R
Changing the frequency may help if your system is somehow frequency dependant. Most are not.
thanks a mill
1. Decreace the spacing of your plates.
2. Increase the area of your plates.
3. Use a soluble compound or catalyist.
If you add a substance such a salt, it will make a huge difference, but you must choose the supbstance carefully. Salt will masivley increase gas production but you will also begin forming other very nasty gasses such as Chlorine. Ideally you would use a catalyist (something that increases the reaction but does not become part of the reaction) Potassium Hydroxide or Sodium Hydroxide might work.
Use a smaller capacitor for C1.
Generator,
I don't know what it is but I doubt it will work. You need to use an LM393
but I need 30hz output with a 500microsecond pulse width...turned on and off every half second.
Also need to be an output of 3-4volts and current limited to 10-12ma
What would I need to change in the circuit/kit to get those results.
Cheers
Using an analogue circuit would mean that your output timing would vary slightly with temperature. You could use a pair of our PWM circuits and an AM Adapter. You would need to adjust to the output you need and measure with a scope. If you want the digital version for precision, we can build it for you, just send your requirements to our custom electronics dept.
I searched a datasheet archive for an LM398 and eventually found one for a 54F398LM (I'm not sure if this is the same as what you asked about). It said it was a "Quad 2-Port Register." It also said it had 20 pins!! The circuit that RMCybernetics used utilizes a much smaller chip with only 8 pins. I have found a few equivalents to the LM393 if you are having trouble finding one. One of the equivalents is the LM2903. You may want to google the datasheet to make sure you have the correct pinouts. Another equivalent, which I have found and used myself is the BA6993. This one has the same pinout as the 393. I hope this helps you, and if it doesn't, you can always google "LM393 equivalents."
And RMCybernetics, I am sorry for intruding on your site, and please forgive me for answering a question directed at you.
Sincerely,
Der Strom
until next time im
going green!
alan
1) VR1 is connction to ???? - connection is not connected at all
2) I will be using these circuit on my Honda 110 cc bike with 12V 5A battery. Can I use this straight or do some modifications to lower the volatage usage ( now the lowest is 9V) to 3V. What component I need to Change.?
I was thinking to use it for Hidrogen Fuel Cell.
2. This circuit will run from 12V directly without modification.
Thank you!
Der Strom
thanks a mill
More input voltage to the coil.
Wouldn't TV horizontal deflection drive transistors work OK for the transformer driver? They're commenly rated 600-800V C-E, I have several from junk TV's. just pulled a 2SD871 out. I built the circuit above, combined it with another simple 555 square wave generator, and watching the output on an osciliscope. Currently getting 600V at 2W with a defection transistor from a very small TV and I'm getting extreem voltage drop when connected to the application. I think I need at least 100W output at 2-3 thousand volts so I can put up with some current leakage without loosing the voltage. My load has a 7K ohm resistance but is highly variable.
NOTE : BD139 connected with 2N3055 in Darlington pair gives very good arcs. (collector of BD139 connected with the collector of 2N3055, emitter of 139 connected to base of 3055, and base of 139 to pulse generator.). Thanks for your benevolent site. -:SOVAN:-
If you use some other square wave source you wll need to add an integrator circiot betweein that and the LM393 so that the 393 is fed with a triangle wave.
sovan,
You can replace both bipolars with a single MOSFET and it should work well. Adding a driver IC for the MOSFET would improve efficiency.
clip of my project with 1 2N3055 with 1 BD139 in darlington configuration.
The Arc is somewhat over than 1 inch.
However that 9 CM Arc that I see from
many a enthusiasts is yet a dream. I
have used 2 100cc motorcycle coils in
antiparallel connection. I have also tried one 800cc car ignition coil but
no good results at all.The 555 immediately breaks(555 seems more stable in antiparallel connection of coils).The P.S. used is 12V , 7.2 A.H. . However MOSFETs driven directly from 555 timer
do not give as good results(Arcs)as
one 2N3055 gives when in darlington
pair with another bipolar.
-: sovan from INDIA :-
Anyway, now to my question: I assume there is one variable resistor to adjust the frequency and another to adjust the duty cycle. Does the 1 M potentiometer control the frequency? Or the duty cycle? Thanks!!!
Sincerely,
Der Strom
1M pot controls frequency.
Sometimes poor connections or wires that are too long or thin will make it more noisy.
Is it possible to use a LM311 ( http://www.national.com/mpf/LM/LM311.html ) instead of a LM393?
Thanks
and what's the meaning for + - in LM393 schema.
thank's :)
how do i know / test the ciruit if it works ? i change the VR1 & VR2 but it seems no effect..
thank's :)
do u have a scheme for the circuir that you sold ? especial for this Power Pulse Modulator..i wanna try to make it
http://www.rmcybernetics.com/shop/cyber-circuits.htm#A21
thank's
The IRF740 will get very hot unless you provide a large enough heatsink.
No, the schematics for our products are not available.
thank's
:)
I already use the etched board to make sure the wiring is not wrong again.
when I connect with DC Adaptor 9 V then I check the output current[using multitester]
is about 1.5 A
then I change the VR2 and VR1 and the result is still the same/doesn’t change.
The voltage output is also didn’t change either
I’m using IRF 530 as a substitute for IRF740. can IRF730 be used too ?
VR 1 = 1Mega Ohm. Using big Potentiometer.
My DC adaptor default current for 9V is 3A.
I wonder where’s my fault. Thank u so much for Any help.
It looks to me like your is not connected correctly. Check the datasheet to identify the pinout of whatever transistor you use.
thank you so much.. i really want to make this mini great PWM :)
do you have detailed wiring so i can make it correctly ? i'm sorry coz i'm still newbie in electronics especially when using active components
thank's
i finally found the clues.. the IRF530 that i've used seems broken.. so i replace it with the 740 ones and it works, also my etched pcb seems have disconected line..
the result of mine tested on 12,4V 3A DC adapter
output
VR1
max = 3.25v
min=2.8v
vr2
max=1.77A
min=0.45A
i wonder why the output voltage drop so much ?
i don't know the frequency cause i don't have the osilloscope for testing it.
i use this for my HHOcell but the HHO gas seems not much produced..
my question is how i can raise the HHO gas production using this PWM circuit?
and which ways that will produce high HHO gas, the low frequency or high freq.?
thank u so much.. :D
A PWM will not increase the gas production. It simply allows you control the rate or production by limiting the average current flowing in the water.
PS: Please don't add so much space in your messages.
i already patched the mosfet into the bike chassis. so the bike's chassis become the heatsink itself.
my circuit was dead. i haven't checked up yet what component was died.
i guest the circuit isn't stable or just can handle small dc amperage.. thank;s :(
The circuit is stable so long as you don't have really long leads. It also helps to place it in a earthed metal case if there is any source of noise nearby. The DC current that it can handle is determined by the transistor used, the cooling method, and the thickness of your power cables and PCB tracks.
i guess the problem is the mosfet that i've used can't resist the heat caused by my bike's dc current.
do u have ideas what mosfet i can use as substitute for the small IRF740/530 one.
i mean the UFO like mosfet like here.
i think it have bigger heat resistant
thank's :)
Does that mean this circuit will fail if I use substantialy less than 10A?
I plan on using this to drive my auto coil for my multiplier
And I further plan on running the whole thing on batteries =P possibly stacked A23's or perhaps stacked 9 volts depending on the design of my auto coil.
I know this circuit and other designs for high voltage multipliers are made for higher wattages but the truth is I am trying for a design that looks the same as a high powered circuit but that runs on 2-20 watts max and that outputs milli amps at best.
Is this circuit still the one for me or do I need another?
Does this circuit still have the full range of the other 0-125k?
How is the best way to scale this up to handle 500 amps peak load at 120 V DC? That would be about twice the power of your super high power unit.
50 IRF740's in parallel on a very efficent heat sink? or is there a higher amperage transistor that will still handle the voltage? It would be 140V peak operating mostly at 120V driving a DC motor. I havn't yet figgured out how to search for an availible transistor in the datasheets for a given job.
I have already used the pulse controller circuit as a low power unit to drive the power bipolar NPN's on a 48V 15HP forklift motor where the control board was dead. That's in an electric hybred car we built, I have a manufactured EV to repair and resell, and then I want to build another hybred
using a KIA sportage my neighbor is pulling an engine out of. I have an osciliscope to help me play with them, and would much rather build a controller than buy the one for 00 US dollars that's avalible.
I have made your circuit and used it to drive an ignition coil and spark plug. However, I am having trouble protecting it. I have tried a freewheel diode and a variety of RC combinations placed across the coild but I still seem to be burning out 555s and 393 when I generate big sparks or turn the frequency up. I don't really understand why this happens - can you help me?
Thanks for your help.
I would like to use either one or 2 of these units to pulse a 12v, 1.5amp fuel injector and immediately when the injector is closed then somehow fire one spark plug from the coil. It seems possible but I dont think I would have need of the var pots on the ignition as I would just wan it to fire after the injector is closed. Is this possible with this circuit? If so, is this something that you can customize for me? Thanks
I would appreciate any insignt on this. I wish you guys had a shop down here in New Zealand as the shipping of one of one of your kits would be a killer.
Shipping to NZ is just £6.19 by standard Airmail service.
The FETS used were IRF540 as they are 100V 32A and I have placed a free-wheel diode across them as well as a neon+resistor and an MOV. seems to help a little but not as much as I would have expected.
I will try and RC circuit instead of the MOV and see if that works any better.
Attached is the simplified diagram.
I got hold of a 12 volt 6 amp power supply and connected it to your PWM circuit as an external power source but the arcs emitted by my ignition coil are even less impressive (hot) than when I had the 18 volt 1.1 amp power supply. I understand the 18 volts would increase the output spark length, but does the output current also rely on the input voltage? I have always thought that the input current controlled the output current, and the input voltage controlled the output voltage. Have I been mistaken?
Thank you very much, and keep up the good work with the site!
-der strom-
Great work! thanks for sharing! i have some questions for this work!
can i use this circuit to generate a pulsed magnetic field? the Peak of B=0.66T
If you have only a small load on your coil, most of the pulse energy is being reflected back to your circuit. I would suggest using a seperate battery for the load and control circuit to minimise voltage spikes on the power rails.
der strom,
The output voltage from the coil is proportional to the input current. Since the coils impedance does not change, applying a higher voltage will create a higher flow of current.
The current ratings on the PSU's are not telling you how much current will flow out of them, it is just how much can flow without it overheating. It is quite possible that your 1A supply can put out 10A for short periods or that your 6A one has a high internal resistance. You should measure the current directly as the numbers on the PSU's will just confuse things.
bin,
Yes.
My pre-amplifying transistor was an NPN bipolar transistor that had a gain of about 120.
Thanks for the help!
--Der Strom--
Try measuring the current through it, then you will know for sure.
bin,
If you use a microcontroler then there is no real need for this circuit. You can connect pots to a microcontroler and write software so it can vary frequency and duty of the output.
PS: Thankyou for your kind donation!
i'm really confuse about this project. i already simulate this project in the multisim but still don't get the expected output.
so can you show me what is the output waveform of this power pulse controller?
is it in the square, triangle or sawtooth signal??
please give me the answer as soon as possible..
thanks:)
I have mounted it like the scematic picture shows, but when i pulse the input, it just seems to make a threshold, and the IGBT gets very hot, then i turn of the power, and short the legs on the IGBT, only then it will turn off?
Have i been using a wrong IGBT?(since the circuit should be ok with other IGBT's)
Or does any of you have an idea, of what to do, to make this work?
Thanks in advance
Palle.
but i still don't get the square wave. i just get the straight line.
is it because of the problem of my connection in my circuit or something else?
in that picture is my simulation from multisim. can you check it for me?
i was wondering what is the causes that occurs in my circuit. thanks:)
Not sure what you mean by "make a threshold", but I guess your wiring is wrong somewhere. It should work with any IGBT. One thing you might try is to put a 10k resistor between the gate pin and GND. This can help switch off the transistor.
hanyss,
You need to crop your image before posting it.
I can see that my picture of the schematics has gone lost somewhere i cyperspace?
I'll try posting it again.
It is not an inverter. The output is pulsed DC. If you get a voltage rise it is due to some inductance in your circuit somewhere.
i a little bit confuse..
how this device work?
i tried to simulate the circuit but i can't get the square wave waveform. the voltage output drop to micro..
When this circuit is built properly with protection from voltage spikes etc, it has a huge number of uses. See our PWM Circuits for details.
so this is the result:
Vmax=11.5V, Vmin= -1.08, Vpk-pk=12.6, freq= 48Hz, Cyc RMS= 4.81, rise time= 33.6us and fall time= 9.2us..so what you can conclude with this result of the output of this circuit. i already got the square wave form. but my lecturer said my circuit is now driving the AC voltage. it is true?? and i'm not clear about the duty cycle and pulse width..can you help me rmc..thanks.
I don't know what you mean by "driving the AC voltage". What AC voltage are you referring to?
Follow this link to learn about duty cycle and pulse width modulation.
Just need a bit of help connecting the MOSFET what pin is what. I have a Data sheet from IR but it didn't help me much.
Thanks for your help
thanks for your help.
Yes it will work with 24V as long as you use resistors to supply the correct voltages to the IC's.
What am I doing wrong here? I haven't had much experience in electronics. I am Just learning, any advice you could offer would be much appreciated. thanks
First thanks a lot for the great project.
I'm just wondering why use two IC? Because I think I have seen a circuit somewhere using a single NE555 timer with two potentiometers to control the frequency and duty cycle.
Also can you please tell me if IRFP250 and IRFP460 will work with this circuit.
Thanks again for your help.
Placing a 4k7 resistor in series with th IC's power input wont make it 12V. You need to use a voltage divider.
Even better would be to use a voltage regulator. There are also several points on the circuit that use some voltage reference. If you change the supply voltage all these will change too. You need to make sure that all the parts that connect to the power (except transistor drain/collector) in this circuit, still connect to 12V.
TheFifth,
Using a single 555 means you can't independantly adjust frequency and duty. Yes those transistors will work.
is the output voltage change when i tune the duty cycle? let say if i use the light bulb as a load..then i set the duty cycle to 80%, is it can change the output voltage across the load or the output voltage is fixed?
The 'on voltage' is always the same, no-matter the setting, but because it is on and off quickly you may measure a lower voltage with a meter. For example if the duty is set to 50% you might measure only 6V even if the 'on voltage' is actually 12V.
The brightness of the bulb changes because the average power changes. At 50% duty, the bulb is actually only getting some power for half for the time. It is because the pulses are so fast that we do not see the bulb flash.
I'm not sure why the motor would slow with 100% duty. Maybe the current is too high and the MOSFET is overheating.
im newbie here...
i have constructed this circuit and thanks to u it works.. for your information i use dc motor as the load.. is this circuit work on ac motor? and what drives the irf740? tq..
No, 100% duty should give maximum speed.
manzz,
No an AC motor needs a totally different circuit.
Im not very clear what is the function of VR2(potentiometer)... can you explain it to me.. tq very much..
And one more thing, can i use two load at the circuit without any changing to the circuit?
Thanks again for your help.
i wanna ask something....
when i test the circuit on oscilloscope, i do get the square wave output. but when i increase the VR1, the graph still the same.. it did expend when i increase the VR1 but it still square wave.. how can i know the duty cycle increase based on the waveform..
VR2 is to adjust the duty of the output. VR1 is for frequency.
You can see about PWM here.
Yes you can connect multiple loads in parallel.
hanyss,
Putting a 10k resistor parallel to the motor wont do anything noticeable.
There must be some problem with your circuit.
I built this project to pulse fuel injectors for cleaning and flowing. It works very good. However I am not able to get duty cycle below 45%? I read to make sure that R2 and 4 are same value and/or reduce value of R2 slightly. Is there anything else it could be? Also, should the 555 reset pin be connected to +12V?
Would there be any difference in using a transister versus mosfet for driving injectors (16ohm). Scope showed better looking pulses with transistor and injectors possibly didn't get as hot.
Thanks again
Dave
Yes, tie the reset pin high. Not sure why you cant get lower than 45% though.
A MOSFET is a transistor. Do you mean a different type of transistor such as a bipolar type? The heat generated in your transistor depends on its parameters such as the 'on state' resistance and the switching speed.
hanyss,
No, you are not understanding how this circuit is working. The 555 is the oscillator. The comparator compares the voltage from C1 and VR2 to give a square wave output for driving the MOSFET.
1. Change the mosfet to a TIP142 transistor
2. Drop the extra volts across a resistor
I have built the circuit with a TIP142 and it worked well at 6V driving a light bulb – now if I want to drop the extra volts where would I connect the resistor? From collector (drain) to ground?
Given that I want to drop 2.5v and current is 800mA does that mean I need a 3ohm resistor? Seems low.
You don't calculate the resistor like that. If your LED is rated for 800mA max and you want to use a 6V supply, then you use ohms law as follows;
R = V / I
= 6 / 0.8
= 7.5 ohms
The resistor must also be rated for enough power;
P = I2R
= 0.82 x 7.5
= 4.8 watts
I will use your suggestions for my testing.
I actually plan to connect this circuit to multiple diode array loads with current draw varing from 0.8A up to 8A - Is there a way that I can keep the output voltage constant at 3.5V under these various loads without having to change resistors?
You should make sure each individual LED has its own resistor that will limit current to within the LED's specifications. This way whatever number of LED's are connected, each one will get the right current.
Laser diodes typically use a constant current regulator, but again, you should use one of these per diode. Taking short cuts will just lead to poor results in the end.
If you want something reliable, use one of our Power Pulse Modulators. The PWM-OCB would work great for pulsing fuel injectors.
I suspect your motor may be too large for it.
This diagram shows how it should be connected with a secondary supply. The V+ at the top supplys the circuit with power, while the V+ (secondary) supplys the load with power. There are two seperate PSUs such as batteries for example.
If your voltage is dropping, this indicates that your PSU is unable to supply enough current, or that you have something miswired.
Yes you can use a resonant load, but be aware of resonant voltage rise that may damage or interfere with the circuit.
You need to calculate or measure your load impedance. Based on your figures, you can do the following calulations...
Z = 12V / 0.18A = 66.67 ohms
If you then work out the current that would flow when the voltage is increased to 105V....
I = 105V / 66.7 ohms = 1.57A
You can see that your PSUs 250mA rating falls well short of this and is therfore unsuitable.
These calculatons are based on Ohms Law.
What is supplying the power to your regulator circuit? I suspect it has too much impedance.
No. 105V / 8264 ohms = 12.7 mA
The capacitor in the tank circuit needs to be charged so the initial peak current will be very high. I'm not going to continue this discussion here as it is not relevant to the article. As I have suggested before; if you need help with your project, you can hire us for project consultancy.
It should work fine from 12V. What are you using for the load?
Check the Ignition coil driver page.
Please see post 1754 on the ignition coil driver page for a basic example. Alternately you could have the BFY51 (or equivalent) with its collector connected to the gate of the IGBT, and its emitter grounded.
You should have a variable resistor in series with the transistor base terminal so that you can adjust how hard it switches.