This circuit was found in a 1977 Radio Handbook. The MOSFET supports an equivalent. Capacitor C must be low leakage.
We found this trebble booster circuit in a 1990 documentation. The components are current, and the...
This circuit was found in an 80s Hands On Electronics. It senses the water level in a reservoir by...
This circuit was found in General Electric documentation from the 1980s. The circuit is intended...