This circuit operates at a frequency of 80 KHz and modulation up to 60 kHz. The circuit is from 1980s documentation. The PUT is an uncommon component today.
This circuit activates a relay when the sensor receives light. The sensor can be any common LDR,...
We found this circuit in a 1980 documentation. With basic changes, including transistors that were...
When a small air current reaches the piezoelectric sensor, a small audio signal is generated and...