This circuit comes from a Gernsback Publications of the 90s. The circuit uses a general-purpose transistor as a sensor. The power supply must be symmetrical.
Rapid Prototyping Boards for 32-bit Applications Include Peripherals, Easy-to-use Interface and...
This is another quick adder that we found in an Electronic Design from the 80s. It also applies to...
This configuration was found in an English magazine from 1965. It is valid for any junction FET. The...