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 two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...
This blocking oscillator was found in a publication from the 50's. The coils determine the...
The TPA3100D2 integrated circuit from Texas Instruments (www.ti.com) consists of an efficient...