Found in 1980s Electronics Design, this circuit covers 4 decades of frequencies with a unique control. A multi-turn trimpot is used for fine adjustment. The frequency range depends on C1.
We found this circuit in a 90s Popular Electronics. It increases the duration of a pulse in a...
This simple circuit detects when a conductive liquid reaches the sensors. The circuit has no...
This converter or inverter uses components that are still common. The transformer is the type...