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 1968’s publication and uses germanium transistors. Equivalents can be...
I found this circuit in an article in a 2003 publication. The circuit is an example of how to...
This 40-second timer uses common components. The output can be used to excite a power stage. With...