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555 pulse gen driver for ignition coil question
Posted by leith aitchison on 6/18/2006, 1:10 am
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Re: 555 pulse gen driver for ignition coil question
Posted by BertHickman on 6/18/2006, 12:31 pm, in reply to "555 pulse gen driver for ignition coil question" Hello Leith, You need to drive a power transistor with the 555 timer. A power transistor is required to do the actual current switching for the ignition coil since the 555 cannot directly handle the primary current. A more subtle problem is that the ignition coil must either be capable of charging your Tesla Coil tank cap on EACH pulse of primary current, OR you will need to add a high voltage rectifier on the output of your coil so that you can charge the tank cap over multiple primary cycles. Either option has tradeoffs, but let's at least find some circuits that will drive your coil. There are a number of circuits on the web for driving ignition coils from a low voltage supply. One of the more popular and simplest circuits is here: The main problem with this circuit is that, when the transistor turns off, a large voltage spike is generated by the inductance of the ignition coil primary. However, this can be easily fixed with some minor changes: Also, here's an example of a slightly different circuit used to power a small Tesla Coil: Here's a little bit different approach that uses a high voltage full-wave rectifier bridge on the HV side of the ignition coil. WARNING: Any time you combine a DC source and capacitors, you run an increased shock hazard - charged capacitors can be quite dangerous, even lethal, especially if they store more than 2-3 joules of energy. Good luck and best regards, Bert
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Re: 555 pulse gen driver for ignition coil question
Posted by Mick on 8/21/2008, 4:13 am, in reply to "Re: 555 pulse gen driver for ignition coil question"
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Re: 555 pulse gen driver for ignition coil question
Posted by Bert Hickman on 8/21/2008, 6:59 am, in reply to "Re: 555 pulse gen driver for ignition coil question"
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Re: 555 pulse gen driver for ignition coil question
Posted by jamshi on 3/11/2008, 6:42 am, in reply to "Re: 555 pulse gen driver for ignition coil question"
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