This circuit was found in the Electronics Experimenter Handbook from 1991. The sensor is a diode and the circuit has a relay according to the voltage used in the supply.
The NE566 used in this circuit and a PLL from Philips Components. The period T of the generated ramp...
This circuit, found in similar versions in other articles in this section, dynamically tests...
This excellent circuit came out in a Japanese publication from 1971. It uses Japanese transistors of the...