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.
We found this circuit in a 90s Linear Technology documentation. The circuit uses components from...
This circuit was found in an English magazine from 1973. The magazine no longer exists, but the...
The oscillator of this circuit operates around 8 MHz, but the output will be at a frequency three times...