This is the typical circuit of a local oscillator for a superheterodyne FM receiver. The circuit was found in a 1980s documentation and is typical of early and early receivers.
The frequency of this oscillator depends on the capacitors, being able cover the range between 1...
This soft starter dimmer was found in a 1980s documentation. We can implement it with current...
Passing between a light source and the sensor will trigger on the relay by a time interval...