This SCR relaxation oscillator was found in an 80's Electronic Design. It flashes a small incandescent lamp in frequency that depends on the capacitor.
The original transistor for this circuit from a 1973 publication is germanium, but a silicon...
This VFO was found in a 1980s documentation. The central frequency is given by the crystal and the...
The sensors in this circuit that triggers when the temperature goes out of a certain range are...