This powerful transmitter for the 27 MHz band was found in a Japanese publication from 1961. The circuit is powered by battery and has the details of the coils given next to the diagram.
In the figure we have the way to use the LM3914 as a scale of bar LEDs or moving point. The...
We found this circuit in a European publication of the 1980s. The transistor could be the BC549. The...
We found this simple continuity tester in a 1995 documentation. It uses two LEDs to indicate...