We found this antenna amplifier or Booster circuit in an Electronics Now from the 90s. The circuit can be implemented with equivalent transistors like the BF494.
We found this circuit in an old English publication. The resistor not indicated can be 2k2 and the...
This switching circuit for contact breaker cars was found in a Radio Electronics from April 1964....
This alarm with sensors in series and parallel was found in the 1995 Encyclopedia of Electronic...