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555 Signal Generator

PostPosted: Mon Mar 17, 2014 1:03 pm
by bomber315
so i have decided to try and tune my coil with the help of a 555 Signal Generator.

I have the circuit built but i am having a hard time figuring out how to make it output high enough frequency to work for this application.

I have been crunching numbers on different calculators online and i dont understand what it takes to make the 555 output 200-350kHz

with my calculations i either need a really small cap or a really small pot... im sure someone has built one of these before, so fill me in with what components to use, PLEASE! thanks!

this is the circuit i have built: ... ble555.jpg

Re: 555 Signal Generator

PostPosted: Mon Mar 17, 2014 2:58 pm
by Frost273
I have built one for me.
I've also checked it on frequency meter and it generates signal in range from 55 kHz up to 450kHz (accelently fine for OneTesla).

Here were I found the schematics: A DIY Tesla Coil Tuner

Just in case I'm attaching my board in Eagle, but it's not quite obvious where anything goes. There's lots of wires comming outside the chassis I have put it in.

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Re: 555 Signal Generator

PostPosted: Mon Mar 17, 2014 4:00 pm
by bomber315
cool. i am sort of surprised that with all the surfing i have been doing i never stumbled into this page.... looks like ill probably modify my circuit to be like this one. i see that it does have a very small capacitor like i calculated so maybe i was barking up the right tree.

so have you used this to tune your coil? does it work well? my multimeter has a setting for freq. so hopefully it will work out for me

Re: 555 Signal Generator

PostPosted: Mon Mar 17, 2014 4:30 pm
by Frost273
Well, yes. I used this method for myself. The deviation of frequencies is around 10kHz +/- inaccuracy, which makes me feel safe to power on the coil.
If a single TC tuner used it won't give accurate result so the external frequency meter is must have.

This pair of tools will help not to blow your IGBTs even on the maximum power. And it's not as expensive as buying an oscilloscope.

Re: 555 Signal Generator

PostPosted: Mon Mar 17, 2014 9:29 pm
by bomber315
Well I have an analog scope but I don't know how to use it very well. Or at least I haven't came across any instruction that clearly say how to measure the frequency with it... this method seems easier for me right now.

Re: 555 Signal Generator

PostPosted: Fri Mar 21, 2014 10:16 am
by bomber315
well i built this circuit...

the pot i bought from radio shack was a piece of junk so i ended up switching it out for a 50k one i had laying around... for whatever reason it didnt seem to affect the frequency range of the circuit... i dont quite understand that, but i guess ill just go with it...

i deemed the on board led to be worthless, as it didnt vary brightness enough to tell

i was able to connect my multimeter on hertz and my scope to the output.

managed to adjust the scope and the signal generator to show a spike in voltage on the scope.

Now its time to test the coil in position with a thin wire for streamer load.

all in all this seems like the easiest way i have found to tune. i may do a write up on how to use this method so that other people like myself don't beat their heads off the wall trying to figure it out. First i have to master the method myself haha