how to convert High Voltage DC into AC without changing Voltage? DO CAPACITORS WORK ON HIGH FREQUENCY CURRENT?

I want to build a Spark Gap Tesla Coil but the problem is that I am unable to find a neon sign transformer locally. so i decided to a voltage multiplier. But its output is DC which means that Capacitors (most probably) not work. so please can you tell me how to convert dc to ac without changing its voltage.

ALSO, I was wondering whether a capacitor will work with high frequency flyback transformers or not.


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iceng2 years ago

Sorry to give bad news, But a capacitor voltage multiplier cannot supply enough current to let an inverter ( that could not even be built ) generate AC from the high voltage DC.

You show innovative thinking and that will make you a successful design electronic engineer after you get some schooling in basic circuit understanding.


iceng iceng2 years ago

A neon sign transformer is the only way to go.

What town and country do you live.

If you could put on that super suit and fly to Reno, I would give you a NT.

SHREYANSH_HV (author)  iceng2 years ago
INDIA......thanks for the offer.
-max-2 years ago


yes, they can operate at high frequency AC. Google capacitive reactance. Just make sure to stay within the limits (peak current, voltage, operating freq.) of the capacitor you choose.

Ok I don't know of any transistors or mosfets that work in the thousands of volts.

As for step up transformers there are microwaves, car ignition coils, oil burning furnace ignition, and flybacks, just to mention a few.

Capacitors of the rating will work with them all.

IGBT bricks are often used to build SSTC's. SCRs can hangle large amounts of power, but are difficult to utilize.

-max-2 years ago

Multipliers do not work well under load. It does not matter whether the input into the tesla coil is AC or DC, as the concept is to simply charge up a high voltage capacitor, and discharge it into an inductor once a voltage threshold (set by the spark gap) has been reached. Once this happens, an LC tank circuit is created and it will 'ring'--or oscillate-- several times before dampening. These oscillations must be as close to the resonate frequency of the secondary coil as possible, so that way the power can transferred efficiently to the secondary coil, and the output can reach a relative maximum. Once the 'ringing' stops, the spark extinguishes and the cycle repeats.

The 60Hz AC is *very* slow compared to this periodic oscillation, so much so, that the discharge of the capacitor into the primary may happen 10's to 100's of times per 60Hz cycle, and the ringing caused by these discharges can be in the MHz! So, as far at the spark gap and rest of the tesla coil is concerned, it does not care if it is powered by AC or DC. Google ZVS tesla coil. It uses a royer (ZVS) oscillator to drive a DC flyback, which charges the capacitor.

There is one benefit to using a NST however: If the capacitor's value is 'matched' with the inductance of the NST output, then this creates *another* resonant circuit, so that power can be "bounced" back and forth between the NST and the capacitor, and voltages can climb up higher than what the NST was rated for. However, this is not required, it just improves the output since this LC resonator will increase peak to peak voltages, thus increasing the potential power delivery to the secondary coil. This is also dangerous, as it is possible to damage the NST with too high a voltage 'buildup,' so this CANNOT be unloaded, the spark gap must fire at a low enough voltage.

-max- -max-2 years ago


LC ringing on mains.png

use a fly-back supply.