This circuit, from a 303 Circuits from the 90s, uses a telephone pickup coil as a sensor to capture power grid noise, thus making it possible to locate electrical wiring.
This circuit generates sequenced pulses to control a stepper motor. The speed at which the pulses...
This battery-powered micropower supply was shown in Radio Electronics magazine in 1991. The...
This Philips circuit of the 70's makes use of components of the time. The DZD40 is an uncommon...