This crystal or galena radio is one of the many versions available on this website. This is from a documentation from the 70s. The coil is formed by 50 + 50 turns of wire 28 in a ferrite rod.
This experimental circuit for moving a stepper motor was found in a 2002 documentation. However, given...
This interesting circuit causes a set of LEDs to flash at a speed controlled by the CI1 in an...
This filter lets a range of 0.1 to 10 Hz pass. We find it in a 1980s documentation, but it can be...