We found this circuit in an American documentation from the 90's. The circuit makes use of general purpose NPN transistors. The 0.005 uF (5nF) capacitors determine the frequency.
This source is indicated for the supply of high-power valve circuits and other types that require...
In the figure we have the circuit of a bistable using two relays. We found this circuit in an...
Found in Popular Electronics, this circuit is intended for testing servos used in model making. The...