This configuration was found in the Texas Instruments optoelectronics manual. PNP transistors support equivalents and the phot transistor does.
This long delay circuit was found in the July 1973 Radio Electronics magazine. The capacitor...
This basic circuit showing the LM3914 “inside” was published in the October 1980 issue of Radio...
Using only one general purpose transistor this circuit is powered by batteries. The lamp of the...