This circuit was found in an English publication from the 70s, an article that teaches how to calculate instruments. The circuit is still current and can be built with an analog indicator of 100 uA.
T Found in a 1992 Popular Electronics, this sophisticated circuit uses two speakers on a different...
We found this circuit in a 1995 documentation. It is a two-channel preamplifier for supplying a...
This timer was found in a 1980 publication. With the BC548 for Q1, an 8-ohm speaker with 6 V power...