This sensitive circuit was found in the August 1971 issue of Radio Electronics magazine. The SCR is equivalent, and the transistor may be a BC548. The load may be a relay.
This circuit was found in the SGS manual of linear integrated circuits of 1982. The circuit...
This grid dip meter was found in old American documentation. The range is from 350 kHz to 1700...
The power supply for this circuit must be symmetrical at 12 + 12 V and the load must be 8 ohms. The...