Hello. I need to make some simple pyrograph for college of mine but am stuck in a process. There is a way to make this ultra simple with PC power supply but for this i need TL494 which is not in any of my power supply's. Anyhow, i have few transformers ( 12V ,24 and one from microwave oven ) so i was planning to do this with such setup, but to do so i need some basic scheamatics or explanation how to make this. Can some one share some schematics or ideas ? Best regards !