This circuit was found in an American documentation of the 90s. Optical resources with the LDR as a lens can help in obtaining directivity and sensitivity.
In this 2001 circuit we have the way to trigger an SCR with a phototransistor. The circuit appears...
This circuit generates signals for adjustments in FIs of 10.7 MHz. The transistors can be BC548 or...
Indicated for applications in the analysis of logic circuits, this circuit was found in 90s Radio...