This circuit is from General Electric documentation from 1970. The transistors can be of general-purpose types, except for the power that can be a BD136.
We found this circuit in the magazine Eletcronics Now of July 1994. The power supply is according to...
This simple circuit produces a tone when triggered by any vibration picked up by the sensor. The...
In the figure we show how two diodes can be used to simulate the center tap of a push-pull driver step....