This circuit uses a wire potentiometer, but the current is much more intense in the control thanks to the 2N3055 which must be mounted on a heat sink.
This circuit was found in old documentation. The frequency depends on R1 and C1. For the...
For low-frequency signals, this circuit transforms a single oscilloscope into a dual-trace. The...
Using the 555 this circuit was found in a Popular Electronics from the 90's. The circuit directly...