When the voltage in the circuit exceeds the value set in the trimpot, the LED goes off and, if a low current buzzer is used, it rings. The circuit is from American documentation from 1999.
In the figure we have the way to make the three-phase control of a motor using opto-diacs. The circuit is...
This circuit for testing the voltage gain of a transistor was found in the March 1953 issue of...
This circuit was found in a PE Hobbyst Handbook from 1992. The second oscillator is a VFO. The...