This circuit was found in a Popular Electronics documentation from the 90s. It is possible to switch the frequency of an oscillator by voltage. The circuit can act as a shield.
This circuit, from a 2002 documentation, checks the logic levels of the inputs, providing a...
This circuit can be used to measure the frequency of a low frequency square signal. The signal can be...
Found in a 90’s Popular Electronics, this circuit uses a component that can be difficult to obtain...