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.
This circuit was found in a 90s schematic manual published in Europe. The circuit uses two PNP RF...
This “zero crossing detector” was found in a manual of operational amplifiers from the 1980s....
In the figure we have an anti-ring circuit with 4093. The duration of the pulse is given by R1 and...