This simple audio signal tracer or follower can be made with a BC548 instead of the original transistor. The output is made in a small crystal phone. The power can be from 5 to 9V.
This 3 and-a-half digit circuit was found in a Teledyne documentation from the 90s. The circuit uses...
September 2016 - can already be purchased at Mouser Electronics the Robot Scribbler S3 from...
Using Linear Technology's LTC4252-1, this circuit was found in a 2005 manual. The circuit makes use of...