This circuit was obtained from HAM Radio magazine in an 80's issue. The FETs are types of the time and the frequency is determined by the crystal. The circuit operates at voltages from 3 to 9 V.
This stage for general purpose transistors was taken from an old technical manual. The circuit can...
The integrated circuit used in this regulator is not very common today. The circuit is from old...
This is one of the many versions of amplifiers with LM386. This was achieved in an old publication (1981). The...