This is the high quality 12V-24V PWM Motor controller circuit, at current up to 20A,using TL494-IRF1405 for working with soft start, adjust pulse frequency
It is a great idea. but It is suitable for an old hand!
A good DC switching power supply circuit form old computer that not used. It has used powerful, durable and works great.
If you have batteries is 1.5V or 3V, but need voltage 9V. This DC converter, can help you, This is 1.5v to 9v step up dc converter circuit using TL496