We found this circuit in a 1973 documentation. The null adjustment trimpot is 10k. The circuit can be powered by symmetrical sources from 9 V. The diodes on the bridge can be 1N4148.
Found in a 90s Popular Electronics, this circuit keeps an LED on when a phone is in use. Can be...
This amplifier stage, obtained in a 1980 publication, has a low input impedance and a high output...
This circuit was found in an American magazine in 1976. It doubles the frequency of TTL signals in the...