This circuit was taken from Maxim documentation from the 1990s. It can be implemented on the basis of modern operational amplifiers. Power supply doesn't have to be symmetrical.
This small power amplifier makes use of an output transformer given its design time. In fact, the...
This circuit is from a 1993 Italian magazine, but it can be easily assembled today. For 110 V,...
This two-way switch or control shows how to control a lamp from two points. This version is from a...