The circuit below was suggested by the Motorola Linear Databook of 1990. The component used is uncommon and the power can be between 7.5 and 12 V.
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...