Found in American documentation from the 90s, this circuit can be applied to other operational ones. We found it in an EDN of the time. Next to the diagram is the response curve.
This is the traditional Hartley Oscillator configuration for high frequencies. For 1 MHz wind 80...
The transistor in this circuit can be the BC558 and the capacitors must be ceramic. Crystals from...
Found in a 90s American documentation, this circuit that was used in cars of the time, detects low...