Found in American documentation from the 1980s, this circuit makes use of components of the time, which are uncommon today. The circuit detects the approach using a sensor formed by metal plates.
This circuit was found in a Ferranti documentation from 1969. The transistors are common types of...
This powerful amplifier with 2N3055 transistors at the output provides a few tens of watts rms on a...
This interesting circuit is suggested by National Semiconductor and is based on an LH0062...