I'm reading Kenn Amdahls book "There are no electrons" to familiarise my self with the magical world of electricity.
Despite Mr. Ahmdahls insistence on the non-existence of electrons, I find my self thinking about them non the less. My current head scratching revolves around the fundamental radio receiver.
I will attempt to describe my interpretation of how it works and then explain my confusion.
An electromagnetic wave induces an AC current in the antenna. A diode then rectifies the current to a intermittent DC current (the book explains it as a way to solve the problem of magnet hysteresis). The intermittent DC current moves a magnet which vibrate a membrane that produces sound. Lastly the current goes to ground (ground being described as a giant capacitor).
My confusion: The AC current pushes electrons in the wire back and forth, but after the diode the current only flows one way. The only source of electron, it seems to me, comes from the material of the antenna. As the electrons pass the diod they can't flow back; how come the radio receiver doesn't run out of electrons eventually.
Thank you beforehand.
/Tentative electron believer.
Best Answer
Here is a circuit diagram of a very simple crystal set and there is a return path for electrons.
$L$ and $C1$ form a parallel resonant circuit the output of which is rectified by the diode, $D$, and then $C2$ and the headphones (resistor) act as a filter with the radio frequencies passing through the capacitor and the audio frequencies through the headphones.