This basic circuit showing the LM3914 “inside” was published in the October 1980 issue of Radio Electronics magazine. Note that R1 determines the brightness and that the power supply is 9 V.
This simple transistor tester circuit was found in the February 1968 issue of Radio Electronics magazine....
This powerful inverter provides a high-quality sine wave signal. I found it in a Radio Electronics issue...
This squelch is activated by its own noise, acting automatically. It is used in communications...