Found in a radio amateur magazine of the 1980s, this circuit uses components that can still be found easily. The circuit is for NiCad batteries.
This circuit is from a publication of the 70s, but it can be easily assembled with the BC548. The...
This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is...
This transmitter was found in a 1993 documentation, but it can be assembled with operators like...