This circuit is from a 1968 documentation using one of the first integrated circuits available at the time, the TAA370. The circuit is powered by 1.3 V using a 200 ohm handset.
In the figure we have a circuit suggested by National Semiconductor, using an operational...
Tone controls for audio applications can also be considered filters that must attenuate certain...
This circuit was found in an Argentine publication from 1973. It uses a common AM coil (50 + 50...