This circuit triggers an alarm when the mains power is cut off. The circuit was found in the July 1990 issue of Radio Electronics magazine.
This 1975 documentation circuit must use a 6 to 9 V symmetrical source and the signal cables must...
With the circuit shown in the figure it is possible to digitally control the gain of an...
The audio amplifier integrated circuit used in this 1990 project is not very common today....