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.
Other operational amplifiers from the same family such as MC34002, MC35001, MC34004 and MC35004 can...
This circuit was found in a Radio Electronics of July 1984. It consists of the traditional 1 A...
This low drift or offset circuit is from an 80's documentation. The configuration can be made with...