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How do i make a radio without the crystals? Answered

Some people have told  me about using a penny to make a radio. The objective though is to make a radio without the crystals

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user
-max-

8 years ago

i figured out u can use an amp instead of a earpiece.

AM or FM?

For AM, all you need is a tuned resonator, a diode, and an earpiece; see https://www.instructables.com/id/homde_radio. A solid state diode -- or the cat's whisker Andy mentioned, which is a primitive diode -- is indeed a crystal, but not a resonant crystal (which is what's usually meant when the word "crystal" is used in electronics).

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user
jeff-o

8 years ago

A crystal is just one way (and the easiest way) of obtaining a stable frequency for tuning the radio.  There are plenty of other oscillator types that would work, too.

Try some of these designs.  Most don't use any 'crystal' but do have some sort of detector.  You can't build a radio without some sort of detector.

The objective? Is this some kind of assignment for a radio-receiver?
Using thermionic valves would get you around "crystals"

L

If you're talking about the simplest of radio circuits, early ones used a piece of galena crystal (a lead ore) in a  cat's whisker detector in the set.  People have also used a piece of coal as the crystal, which performs the same function - you have to probe the whisker around on the coal until you find a spot which works. 
OK, it's still a crystal, but not an encapsulated crystal diode.
If you're talking about a more advanced design than this, then you have no chance.  Transistors and diodes ARE crystals.

http://sci-toys.com/scitoys/scitoys/radio/three_penny/three_penny.html