This voltage follower or amplifier with unit gain uses an unusual operational amplifier nowadays. The circuit can be implemented to use modern operationals. The power supply must be symmetrical.
Because it uses TTL integrated circuits, this siren must be powered by 5 V or as indicated with D1 to...
This current boosting circuit uses an op-amp and 3 transistors. The current depends on Q1. The...
This simple circuit with bipolar transistors is from a 1970s American documentation. The RF...