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 documentation for radio amateurs from the year 70. Its purpose is to...
This circuit is from old documentation and can be assembled with 2N2646 for the unijunction and...
This circuit for tape recorders was found in the February 1990 Radio Electronics magazine. The...