I am looking to build a square signal generator tuned to ~25 Hz at a voltage of ~90 V AC that can output ~400 mA. I've searched around the internet and tried a few things but I've had no luck. My original idea was to have an Arduino and a LM741CN output a square AC wave and then attach that to a transformer to get it to 90 V AC. I achieved the square AC wave, but it only outputs about 2.5 V AC. Getting that far I was looking into transformers but low frequency transformers are not as easy to come by as I thought, I tried building one but the core I had on hand was not big enough to handle the amount of wounds needed.
My overall question here is: Was I heading in the right direction or is there a better way that I have not found yet?