This is a typical point scale or moving bar circuit with the LM3915. We found it in old American documentation. The operational amplifier supports an equivalent modern type.
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...