I am just tring to built a 4kv output circuit. I have bought from a ebay this circuit to produce 250v AC from 12v DC. I tried to biult this using
3kV 10nF ceramic caps and 1N4007 (1A, 1000V) diodes but for some reason it does not work. Have anybody any idea why it does not working ? Also i tried to connect at the output of the ebay circuit some transformers and they also does not work. I tried a 1/2 homemade transformer and it didnt worked. Also i tried a 220v/12v transformer to see if it is going to work and still did not worked. I am not an expert in elecronics and i am still learning so my apologies if it looks really simple to all of you.

 

Although the diode circuit built is often referred to as a voltage doubler, in reality it is a voltage ladder. The output of each doubler stage increases by the input voltage. So in your circuit where you have a 220Vac input, the output of the first voltage double stage will be 440Vac, with the output of the next doubler stage being 660Vac (not 880Vac) and so on.

So you do not have enough doubler stages to reach 4kV with a 220Vac input.

I suggest you search ebay for a ‘high voltage generator’ with the output voltage and current you require.

 

Yea that is true i as thinking to built a 8x2 stage for 4kv but it looks like my circuit does not work at all. I built a 2x4 stage already and the voltage i am taking is about 20-30v dc for some reason. Also why transformers does not work when i connect them to the output of that circuit ?

 

Ok i just did found that the voltage multiplier was working good but i fount that i had to charge some capacitors in order to find out if it is working. The circuit from the ebay charged the capacitors at max 300v for some reason and very slowly while i tried it with a bug zupper circuit and the results was impresive. For some reason the bug zupper can charge the capacitors better and easier rather than the ebay circuit. I guess the ebay circuit has a poor quality that is why. I will try nrxt to built a voltage divider so i could measure the voltage.
A question that i want to ask is, if i have for exapmle 5 same capacitors in series and i would charge them to 50v, that means that each one will get 10v right ? So what if i put some capacitors in series, try to charge them to max then measure one of them ? Will this way be an acurate way to measure high voltage ?

An another question that i have is, lets asume i have 5000v 10μf capacitor and a small circuit that it can slowly charge it. Is there any posibility that the capacitor can reach some high voltages without achieved already the 10μf capacitance ? Is there a posibility for example to reach 2000v and 2μf capacitance ?

 

I just tried to built another inverter circuit based on 555 IC

I have changed the value of R4=1K, R5=47K, C5=1nF in order to bring the frequency from 50Hz up to about 15kHz. This also kept the duty cycle just slightly over 50%. I did it because my voltage multiplier use 3kV 10nF ceramic caps.
The Vout from the transistors is about 11v. I checked the voltage through a 12v/220v step down transformer in reverse and i took only about 80v while transistors stared to heating up, anybody got any idea why this is happening ? I am tried to produce about 500v AC with a step up transformer, and further increase with a voltage multiplier to about 4-5kv

 

Hello,

If the transformer is a standard mains transformer that is designed for 50 / 60 Hz, it will have very poor performance on 15 kHz.
When you want to use 15 kHz, have a look for a high voltage transformer from an old CRT television.
That usualy works in the range of 15 to 16 kHz.

Bertus

 

Thank you berthus for your reply. Do you mean the flyback transformer or all TV transformers in general ? Can i make my own transformer so it will output about 500v ?

 

I found at 15kh for some reason transistors produce heat and whistling noise while on load. Is this normal to happen ? Is there any way to improve the circuit by changing the TIP transistors with some mosfets ?

Thanks