I would expect an antenna capable of providing the requisite power for an LC circuit would be a tad more elaborate than what's needed for a crystal wouldn't it?
No. A crystal radio works the same way. The first LC circuit is the antenna and (usually) a capacitor; that collects the energy over a specific frequency range, and all the crystal does is rectify it; it performs the function of a diode.
A capacitor (in early sets, this could be inherent in the wires or the earphones themselves) then changes it from uni-polarity RF pulses to a more-or-less smoothed audio signal.
In a modern radio, the semiconductor diode does the rectification, so the crystal is no longer needed. There are diodes (ex. germanium, schottky) with much lower forward voltages (and much higher reverse voltages) than your typical iron pyrite or galena crystal + whisker; this means that a diode-and-LC based replacement for a crystal radio can capture smaller signals, and survive larger ones, such as static discharges.
Anyway, maybe it's just personal bias, but I still maintain that the good old crystal set launched the career of many an electrical engineer. I know it amazed me when I was a little kid. The thing was practically magical.
(Score: 2) by fyngyrz on Wednesday December 05 2018, @02:23PM
No. A crystal radio works the same way. The first LC circuit is the antenna and (usually) a capacitor; that collects the energy over a specific frequency range, and all the crystal does is rectify it; it performs the function of a diode.
A capacitor (in early sets, this could be inherent in the wires or the earphones themselves) then changes it from uni-polarity RF pulses to a more-or-less smoothed audio signal.
In a modern radio, the semiconductor diode does the rectification, so the crystal is no longer needed. There are diodes (ex. germanium, schottky) with much lower forward voltages (and much higher reverse voltages) than your typical iron pyrite or galena crystal + whisker; this means that a diode-and-LC based replacement for a crystal radio can capture smaller signals, and survive larger ones, such as static discharges.
I think you're absolutely right on that one.