This wired intercom circuit was found in an English publication from the 80's. The integrated circuit can be replaced by an equivalent, just like the transistor which is a general-purpose type.
The circuit shown in the figure serves as a pre-amplifier with a voltage gain of around 12 times,...
Based on Texas Instruments documentation, this circuit serves for sensor interfacing. The circuit is...
This article is from a publication by A. Fanzeres from the 70s. We kept the original text. This...