This bargraph circuit was found in the January 1986 issue of Radio Electronics magazine. It is based on the well-known LM3914 and has two of them in cascade driving a good number of LEDs.
Connected to the output of a small amplifier or receiver, this circuit triggers a relay in the...
This oscillator version is from an RCA documentation from the 1970s. Transistors support modern...
We found this circuit in an American documentation of the 80's, being indicated for the test of...