I need to build a circuit which does the following:

20kHz square wave amplified to high voltage with a transformer which has both a positive and negative output. I need the outputs to switch polarity every pulse.

How can this be done?

 

I need to build a circuit which does the following:

20kHz square wave amplified to high voltage with a transformer which has both a positive and negative output. I need the outputs to switch polarity every pulse.

How can this be done?

A step up transformer with a center tap can do that, if it's carefully terminated.


eric

 

Can you explain in detail how that works?

 

Can you explain in detail how that works?

You can generally pass a square wave through a transformer if you avoid any self-resonant frequencies, and it's got enough bandwidth to pass at least the fifth harmonic. For example, at 20 KHz, you want a transformer that's flat up to around 100KHz. Most of your high quality switching power supply transformers can do that. You need to put a matched load resistance on it, however, or it may "ring" which may or may not be a problem. How critical is it to have a very sharp square wave on the output?

eric

 

From what I can tell it's not critical.

 

Hello,

For what do you need the high voltage ?
How high is your high voltage ?

Greetings,
Bertus

 

The high voltage will be used to charge a capacitor with a polar liquid dielectric. It has been said that the liquid dielectric can be heated, I'm doing it for a science experiment but I don't think it will work.
500V-1000V will be plenty

 

Hello,

How many current will flow in the dielectric ?

You could use a inverter like schematic with a CT transformer like eric siad.
Here are some schematics used for fluorescent lamps.
http://ludens.cl/Electron/Fluolamp/fluolamp.html
The last one is designed for ca. 25 khz.
(You can drive the transistors with a controlled oscillator in stead of selfoscillating).

Greetings,
Bertus

 

I think the secondary will be less than 100mA.

 

Hello,

So you end up with 50 to 100 Watts.
Then the proposed schematics I shown you are to small.

Perhaps you can scale it up.

Greetings,
Bertus

 

I'll keep working and researching and see what I can figure out!