With this circuit found in an American documentation from 1969 it is possible to vary the selectivity (Q factor) of a tuned circuit. The operational is from that time.
This source can supply currents up to 1 A. The circuit is from Motorola's 1993 Linear Interface ICs....
The purpose of this receiver is to monitor the signal from a nearby transmitter. It was published in an...
In the figure we have a symmetrical power supply stabilized by a zener diode. Transformer and...