This circuit with the CA3059 was found in the July 1995 Elexctronics Now magazine. The signal must be DC, and the circuit is not isolated from the mains.
We found this test circuit in a March 1967 Radio Electronics. The circuit uses a zener-regulated supply and...
This amplifier for small cassette tape players was found in an English documentation from 1969. The...
We found this circuit in a 2005 Linear Technology manual. The resistor is calculated for the...