This high-impedance headphone circuit was found in a 1990s William Sheets. The power is low, but the high input impedance makes it useful for radio applications.
We present a DC-DC converter circuit that can operate with input voltages from 2.4 V to 14 V and...
We found this circuit in a 1977 Radio Shack brochure. Transistors can be the most modern BC548 for NPN...
This circuit can be used as an input shield for microcontrollers or other TTL circuits. The power...