This 1968 Mallory circuit uses an uncommon integrated circuit today. The circuit has a 30 to 20,000 Hz response with lower power and is powered by 12 V.
This power supply for model railroad was found in a February 1961 Radio Electronics Magazine. The...
This interesting circuit of the American publication Electronics Handbook Volume XIII 1993 shows a...
Found in a 1978 publication, this circuit uses germanium transistors and drives a small 20 to 50...