We found this circuit in the June 1987 issue of Radio Electronics magazine. With it, it is possible to receive signals from the bands determined by the crystals in a common medium wave receiver.
Found in Maxim's documentation, this high frequency circuit uses period components. The graph...
We found this circuit in an 80's Radio Shack publication. The circuit uses a company buzzer, but...
This interesting FET-tester circuit was obtained from an old American documentation. The bipolar...