This circuit is from 1999 documentation. The integrated circuit used is not very common today. Both transistors are used if the motor current is greater than 500 mA.
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...