This elementary receiver with a crystal earphone was found in Japanese documentation from the 1960s. The coil has 60 + 40 turns of wire 28 to 32 in a ferrite rod.
Only the right combination of the positions of the 6 rotary switches of 1 pole x 10 positions of...
We found this circuit in a 1977 Radio Handbook. The lamp is the critical component, being 120MB at the...
This 1964 Electronic Design circuit uses a photo-FET as a sensor. The component is rare today. |...