This circuit is from an American 80's documentation. The circuit indicates when the voltage of a 9 V battery drops below 7 V. The transistors can be BC548.
Suggested by Siliconix in documentation from the 90s, this amplifier has its gain digitally...
January 2017 - Pulse Electronics ER11 transformers with high insulation can be obtained from...
This circuit is from an American 80's documentation. The circuit indicates when the voltage of a 9 V...