This 3-step circuit for generating digital signals was found in the November 1976 issue of Radio Electronics magazine. The maximum frequency depends on the flip flops.
We found this circuit in a 1987 documentation. It is a multi-tester with neon lamp and LEDs...
This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...
We found this circuit in a Texas Instruments optoelectronics manual. The audio modulator serves for...