Found on a 1969 EDN this circuit switches a current from a digital control signal. The impedance of the circuit ON is approximately 10 ohms. Modern equivalent transistors may be used.
With the name of transitube we find this MW receiver in documentation from the 50's. It uses a...
This circuit can provide both positive and negative voltage outputs from 2 to 12 V with current up to...
In critical applications of the RS-232 interface, the danger of induced voltages in the cables must...