Found in a 90s R-E Experimenter Handbook, this circuit has a greater gain than the previous one for presenting two stages. The integrated circuit used is uncommon today.
This series and parallel sensor circuit was found in Popular Electronics from the 1990s. Any SCR...
This antenna tuning circuit was found in a Popular Electronics from the 90's. The coils depend on the...
Applications for this circuit include hearing aid, stethoscope, etc. Transistors are general...