The purpose of this circuit is only to increase the input resistance of a multimeter, since there is no voltage gain. The batteries are 9 V and operational equivalents can be used.
This circuit applies to other operational ones, other than the one indicated. The formulas next to the...
This circuit can source 3 to 12 V with currents up to 500 mA depending only on the transformer....
This relay circuit is intended for reversing small DC motors. The circuit is from an old...