This small commercial radio for the MW band with germanium transistors was found in Japanese documentation from the 1960s. The circuit is powered by a 9 V battery and has a 455 kHz IF.
This alarm uses several sensors that directly trigger a sensitive relay. A larger relay can be...
This circuit for counting down pulses was found in the September 1983 issue of Radio Electronics...
Indicated by Popular Electronics to be used with a car headlight, this circuit can also have...