This circuit was found in the February 1997 Electronics Now magazine. The circuit has a power supply for the NE602 and free inputs and outputs for projects.
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...