Found on an 80's Elektor, this circuit uses common components, being the diode a general purpose germanium. The coils select the frequency range of the indicator that reaches 60 MHz.
This precision circuit can provide timings from 0.2 milliseconds to 3 minutes accurately. The...
This circuit uses a phototransistor as sensor. The changes in the resistance of the transistor,...
We found this circuit in 1980s documentation. It can be used independently as CW or by exciting a...