We found this test circuit in a March 1967 Radio Electronics. The circuit uses a zener-regulated supply and analog indicator.
This simple circuit was found in an English magazine that no longer exists, January 1970 issue. It is...
We found this circuit in a 1977 National Semiconductor audio manual. The integrated circuit is the...
This circuit was obtained in a Popular Electronics of the 90s. It against a kitchen hood based on...