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.
We found this circuit in a technical documentation from the 70s. It can be implemented with more...
We found this shield circuit in a 1991 technical documentation. The phototransistor can be...
This circuit was obtained from a Radio Electronics from October 1963. The 4 transistors must be...