This circuit triggers an LED when the input signal exceeds the peak, or the value set in RV1. The transistors can be the modern equivalents BC549.
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...