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 circuit is from the time when photos were revealed in darkrooms. We found it in a 1968...
This high-gain circuit was found in an American publication from the 1990s. The circuit can use...
This circuit provides an output of 5 to 10 V at its output from inputs of 1.5 to 4.5 V. The output...