Published in Popular Electronics with the curious name of Obnoxious Noisemaker, this 1968 circuit generates random sounds that are reproduced on a loudspeaker. The power transistor can be a BD136.
This configuration is from an old integrated circuit manual. The circuit can be applied to modern...
Texas Instruments has downloadable documentation on designing digital isolators. The Digital...
The purpose of the circuit of the figure is to control a servomotor remotely using a simple signal...