This relay shield circuit for old computers was found in January 1983 Radio Electronics magazine. The relays are sensitive types with currents up to 200 mA.
With the circuit in the figure, it is possible to control the amount of heat generated by the...
This circuit allows to increase the output power of a 741 as an amplifier. The circuit is from a...
This 2000 circuit can be used to match the low impedance of a microphone to the high input...