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 uses a crystal phone and can be built with more modern transistors like the BC548. The...
The resistors in this circuit marked with * must be within 1% tolerance. The circuit is from the...
The existence of field effect transistors at the input of the integrated circuit (operational...