This detector with ultra-low deviation was found in an American documentation from the 90s. Operational amplifiers are from that time. The power supply must be symmetrical.
In this circuit found in a 1991 publication we can use the 2N2646 unijunction transistor and the...
This circuit transforms your low sensitivity analog multimeter into an electronic voltmeter with...
This 10-step voltage indicator was obtained from a 1980s publication. The circuit is based on an...