This simple circuit to monitor the frequency of the power grid uses an analog indicator. The adjustment trimpot can be 4k7 and the indicator is 100 mA full scale.
This conventional power supply circuit with the LM317 was found in a 1987 publication and its...
This circuit is from a 1972 German magazine Funkshau. The circuit can use BC548 transistors...
Found in a 1968 Motorola documentation, this circuit operates at 1 kHz and can deliver 20 V from...