Using an LDR as a sensor, this circuit is from the Radio Electronics magazine of December 1984. The operational amplifier is the 741 and the source must be symmetrical.
We found this bench circuit in a Radio Electronics magazine from July 1962. The transistors are...
This circuit is from an 80's documentation. The circuit makes use of a component of the era, the...
This Linear Technology circuit can measure currents from 100 pA to 100 uA. The circuit is from the...