This old indicator circuit indicates only when the fuel reaches the sensor level. The integrated circuit is not common today. The circuit was found in documentation from the 1980s.
This circuit triggers an alarm when the mains power is cut off. The circuit was found in the July...
This acutely tuned circuit was found in American documentation from the 1960s. The transistors are germanium...
This small AM transmitter was found in American documentation from the 1980s. Transistor support...