We found this sensitive high input impedance voltage amplifier in the November 1970 Radio Electronics magazine. The circuit is powered by 18 V power source.
This conventional astable multivibrator circuit with operational amplifier can be found elsewhere on...
Using red LEDs with ignition voltages of the order of 1.5 V we can make a multiple voltage...
This old circuit (1968) uses a germanium transistor to drive a relazy from a switch. The circuit...