This biestable touch circuit was found in American 1980s documentation. The circuit must not be powered by a source without a transformer. Sensitivity depends on the 10 M resistors.
The sensor for this circuit, found in a 1992 publication, is a phototransistor. The power is...
This circuit can generate signals of frequencies up to 1 or 2 MHz, tuned in the capacitor. The...
Suggested by Philips documentation from 1968, this circuit uses components from the era that can...