Hi everyone,
I want to build a simple HV inverter to test the DC leakage of the bus capacitors on the various devices I repair at work. I found an old 575VAC to 24VAC transformer in a pile of scrap. There's no info except voltage written on it, and I assume it's around 100-200VA looking at its size. I'd like to use it as a step-up converter, to hopefully bring the rectified voltage up to around 750VDC. I don't need a lot of current, 100mA would be plenty.
At first I was thinking of using a simple 555 circuit, feeding a ~60Hz square wave into the transformer with the help of a drive transistor. However, I'm afraid the lack of efficiency will overheat it, or prevent my output from reaching my desired voltage. Is there a way I could filter the output of my transistor to approximate a sine wave, and if so, how can I calculate the value of the parts I will use (capacitor, inductor or even resistor)? These equations are faaaaaar away in my brain, and to be fair I'm far from an expert in analog circuit tuning...
My other solution would be to program a PIC microcontroller to output a modified sine wave to the tranformer, and maybe adding a touch of filtering. I guess it would be more efficient to do it that way, but I'm a bit lazy and I'd rather not test the operational limits of the computersaurus (read: v.slow computer) I have at work, while trying to program a few lines of code

Oh! And I almost forgot... It needs to be variable too! No need for fancy doodads, varying the input voltage (or drive voltage) can do just fine.
I'd like to know your opinion on the subject, and maybe even good ideas I did not think of. The simpler the better!
Thank you
