Found in a Popular Electronics from the 90s, this circuit uses common components with several operational options, including the use of an optocoupler that allows its application in a shield.
This is a circuit with a period component that consisted of a voltage reference. The circuit is...
This experimental circuit was found in a technical publication from 1976. The diode can be of...
Tone controls for audio applications can also be considered filters that must attenuate certain...