This sensitive circuit was found in the June 1995 Electronics Now magazine. R1 can be from 10k to 1M depending on the desired sensitivity. Power is supplied by the relay.
This amplifier stage was found in a 1956 Sylvania manual and has an unusual configuration with a...
In the circuit shown by figure 1, a10 mV AC signal applied to the input produces a 1 V signal in...
This circuit was obtained in 1974. It serves to indicate the tuning of stations on a common...