This circuit, which appears elsewhere in this section, is from a 1969 Electronic Experimenter Handbook. The circuit uses components that are still common.
This old receiver (1967) uses germanium transistors from the time and coupling transformers,...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
A negative pulse applied to the input of the circuit shown in figure bellow turns on the relay....