Found in a Hands On Electronics from the 80's this circuit allows the reading of low resistances in a common multimeter. The circuit consists of a constant current source.
This bidirectional optical switch detects the direction of movement of an object that passes...
For the locked trigger we also have the circuit shown in the figure. In this circuit we also have...
This circuit causes an LED to blink when night falls. Sensitivity is set at R1 and the blinking...