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.
The circuit shown is from old English documentation and can be made with BC548 transistors for low...
This sequential relay actuation system circuit for traffic lights was found in Electronics Now...
This circuit limits (clip) the intensity of a signal, according to the setting of P. The circuit is...