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 VU circuit has a different effect given using two 4017. The circuit is from 1997...
This circuit was found in a Motorola documentation from the 70s. The components are from the time,...
This Schmitt trigger in current mode for frequencies up to 50 MHz was found in a 1969 Motorola manual....