Tesla Attempt

[rave154]

Hi all,

in my on going journey to at least 'try' and replicate some of what Tesla did ( albeit on a smaller scale), i have started this thread, both for myself, and others who wish to do the same.

Readers Digest version of where i am at present and how i got there.

Started with Aromaz's circuit, then tried to hook up a basic 555--> 2n3055--> ignition coil, works for a while but then the 555 pops it clogs, or blows its cookies due to the high voltage.

Found these two circuits which offer protection...

Ignition Coil High Voltage Circuit

Ignition Coils

and under the adive of Aaron, am also going ot try opto-isolating the 555 from the high voltage side.

soooo...... got the opto isolator today so i am ready to go with that, but ive never worked with one before and as all of this is pretty much a learning experience for me, i need help with the circuit, the attachment shows how i "think/hope" it gets wired up..

the opto is a "High Voltage Opto Isolator4N25"

Thanks in advance.

David. D

[Bit's-n-Bytes]

rave, The opto cannot be directly hocked up to the coil. It will need to drive a base of a transistor or FET.

Hope this helps.

[rave154]

thanks bits

Bits, so i can use the output of the opto, to drive a 2n3055 which in turn connects the coil .....but....to the same battery as the 555....or a second seperate battery for isolation purposes?

Thanks :-)

David. D

[rave154]

mark-2

bits,

hows this look?

[Bit's-n-Bytes]

IMO I would start with this kind of setup (only for reference). Please check all suggested setups of this nature as I will not be responsible for a circuit gone wild.

Hope this helps.

Bit's

[rave154]

try again

heres my latest attempt with my pathetic knowledge of electronics

even IF this sschemtic is correct...

what are the values of R1, R2, R3 ?

Thanks for any help.

David. D

[Inquorate]

Values for R

Try this calculator; I've always struggled with 555's so that's why I'm mostly keeping quiet just now..

555 Timer Calculator

Love and light

[rave154]

inq,

thanks for the 555 thingy, it iwll come in handy once i have the complete circuit up and running.

My problem at the moment is, where on the datasheet for the 4n25 does it show the voltage across the diode inside the opto, also the max current for the same? I have never seen a datasheet before so its a bit confusing with all the new terms etc.

Here is the datasheet...

http://www.datasheetcatalog.org/data...child/4N25.pdf

thanks for any help forthcoming.

David. D

[ren]

You can use the opto to isolate your 555 from the power coil.

Your output (pin 3) of the 555 should pass through pin one and out pin two, into a fixed resistor (say 300-400 ohms) ad back to ground. You can use a smaller battery to supply this part of the circuit (the timing side).

You then use the transistor output in a darlingto configuration, or to turn on a fet to fire your ignition coil.

Regards

[Bit's-n-Bytes]

Rave, is this a normal auto ignition coil? If so I think your diagram shows it with the polairty reveresed. The source battery should feed the positive side of the coil and the negative side should hook to the collector of the transistor. The transistor, biased by the triple 5 and opto should provide a quick connect and disconnect of the collector / emitter to ground (negative side of the source battery). This action should cause the coil to fire (spark on the high tension side).

Hope this helps.

[rave154]

BITS,

my circuit is based on this..

Ignition coil driver by IC 555 + 2N3055 | Circuit Project Electronic

i simply want to add "isolation" between the output of the 555 and the input to the 2n3055 as im burning up 555's like theyre going out of fashion.

Thanks,

David. D

[Bit's-n-Bytes]

You may want to install a 1n4007 or equivant diode between the source and input coil terminal. You may be getting a BEMF spike from the coil primary (low side) coming back and taking out your triple 5.
Just a thought.

[ren]

BITS,

my circuit is based on this..

Ignition coil driver by IC 555 + 2N3055 | Circuit Project Electronic

i simply want to add "isolation" between the output of the 555 and the input to the 2n3055 as im burning up 555's like theyre going out of fashion.

Thanks,

David. D

hi David.

I posted above on how you use an opto isolator to protect your 555.

Of course you don't have any idea if I know what I'm talking about, or perhaps you didn't understand what I was saying. I can explain it clearer or perhaps show you a diagram.

The trickey thing with the ignition coil is that it's primary is connected to it's secondary. This makes it easy for inductive discharges, which have been stepped up by the turns ratio, to pass through and damage sensitive components.

But, it might not be the solution to your problem. I've had a pwm chip pulsing fets and transistors on an ignition coil with a spark gap connected back directly to the circuit and run them fairly hard without any dramas.

Regards

[rave154]

replies

Thanks all you guys for the help :-)


Im off work till monday now, more parts arriving today..so plenty of play/work to do.

I will try the ignition coil wired both ways (+ ) & (-) with just a bare 555-->2n3055 with a diode on the positive rail going into the coil ? see if anything blows...and also do the opto which i think i have working ok so far, will try it with a lil light bulb or something before trying the coil.

Looking ahead.... assuming i get the 555 going well and can do some experiments & observations, it appears the 555 has a bit of trouble above 20Khz(depending on brand )....and really i want to eventually get into the Mhz range (as per Tesla)...any thoughts on how this might be achieved eventually?

Thanks again for the help

p.s Ren, a diagram would be very helpful for me yes :-)

Ahimsa,

David. D

[rave154]

a lil progress

Hello,

here is my latest circuit attached,

i have tested it with a 12 light bulb instead of the ignition coil and it seems to work ok.

Do i need to add Diodes anywhere for extra protection for the 555 / 2n3055 ?

If so, where?

Thanks,

David. D