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 low-pass filter was found in an American publication from the 80's. The circuit uses an...
This continuity tester for low resistances was found in an English magazine from 1978. The circuit...
This low-pass filter with 741 op and symmetrical source was found in the August 1993 issue of...