"Bradley1234" writes:

"Sam Goldwasser" wrote in message
...
"Bradley1234" writes:

"Sam Goldwasser" wrote in message
...
"Bradley1234" writes:

"klasspappa[remove]" wrote in
message
...
A diod is a diod, not a resistor.
See it as a current source, and put it into a opamp to form a
current
to
voltage converter...


A diode is a variable resistor.

the circuit reacts around the depletion region to increase or
decrease
it.
When the p type and n type silicon meet, the charges mix to form a
neutral
region which is resistive. if the applied electricity is on one
side it
makes that neutral region expand out, if its the other way the
neutral
region is compressed

Not really.

Then please to explain me how silicon diodes work? All this time I
thought
it was the depletion region but its something else?

If my simplified explanation of the solid state physics involved in PN
junctions is incorrect Im grateful to learn where Im wrong.

Please Google "Photodiode principles". There were 33,100 hits but
the first one is adequate. Thanks.

I did, and it still explains similarly to what I said. Ive worked on the
design of semiconductors, lithography, processing, doping, circuits design,
and enough circuit testing to be content with, and have trained and shared,
possibly the wrong information with dozens and dozens of people. maybe
more.

I enjoy studying, but to say just go do a google search? Id expect any such
searches will simply verify and validate what I said.

Did you do the search? Here is the first sentence of the first hit:

"When these diodes are exposed to photons of energy greater than 1.12 eV
(wavelength less than 1100 nm) electron-hole pairs (carriers) are created.
These photogenerated carriers are separated by the p-n junction electric
field and a current proportional to the number of electron-hole pairs
created flows through an external circuit."

That is the most simple explanation of how a photodiode works. It's not
a variable resistor but a a light to current converter.

A device like a cadmium sulfide photocell is a variable resistor, controlled
by how much light falls on it. That's totally different than a photodiode.

I agree that a lot of Web search returns are useless - in fact this one
goes on to talk about other things that aren't directly relevant, it is
a start for many thing.

I'll let others comment on whether your explanation is similar to this one
but unless I missed something, you didn't even bother to mention anything
about a photodiode, only a normal PN diode used in an electrical circuit.

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