This low frequency oscillator circuit was found in an Electronic Design from the 90s. The transistors are common types, and the frequency is given by the crystal.
Assembled with SMD components this circuit can be very small. The range is a few tens of meters. We...
With the circuit shown, obtained in a 1980 publication, a reed-relay is activated with a resistive...
This circuit is a shield for microcontrollers and computers drivind high power loads. In the...