What??? That makes no sense whatsoever. Provided you include a resistor which will limit the current to a safe value, my advice to you would be to stick with the relay.

OK but just to clarify, can I connect the ground of the capacitor and 5v signal together and the signal to base to switch a high voltage?

 

There is a charging circuit charging a capacitor to a few 100 volts. To the capacitor connected is the primary of another transformer. When the transistor/relay is off the capacitor is charging and when it is on current flows from the capacitor through the relay/transistor and through the primary.

Must be missing something here. Why not eliminate the capacitor? Just feed the secondary of the first into the primary of the second transformer.

Nah, its just a small pulse for a tiny fraction of a second.

So is a lightning bolt.

 

If

Must be missing something here. Why not eliminate the capacitor? Just feed the secondary of the first into the primary of the second transformer.



So is a lightning bolt.

If I eliminate the capacitor, then the max current I can draw as a pulse is reduced.

A lightning bolt is capable of much higher voltages at a high current for a longer duration. The capacitor I am talking about is 3.33 uf so the current I mentioned is a small pulse only.

 

From what I am getting from this you just want to make HV arc discharges from a HV transformer or some sort of engine ignition coil with a 555 IC as the control which if so that pretty easy to do.

What I have done is to use two ignition coils wired in reverse series so one is postive firing and the other is negative firing giving twice the arc voltage between the two HV outputs as compared to using one coil.

Ideally using two old 6 volt coils on a 12 - 24 volt source works best provided your power source and switching device can support that level of amp load. Also for the primary side of the circuit keeping the standard condenser that was originally made in the old points type ignition in parallel with your power transistor or mosfet or a pair a of them in parallel with each coil makes a big difference in how strong of secondary sparks you will get.

As for the switching device I recomend using something rated for at least 3x the circuits peak amps and at least 10X the circuits working voltage as an absolute minimum requirement.

For the 555 IC circuit if you can set it up to have both independently variable frequency and duty cycle adjustments that is best. With that and two 6 volt coils running off a 24 volt power source with a rather short on time duty cycle you should be able to easily get a clean sharp 3+"spark between the two HV secondary leads.

Just don't touch it. I won't kill you but it will be a experience you will remember and put an active effort into avoiding doing again for the rest of your life!