Crystal Radio

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I have received a number of emails regarding schematics for crystal radios. After about the third email, I figured that I may as well put one on my page. So here it is. The circuit is very simple with only 5 parts, but performs very nicely when used with the right size antenna.

Schematic

Parts

Part	Total Qty.	Description	Substitutions
C1	1	Tuning Capacitor (See Notes)
D1	1	1N34 Germanium Diode
L1	1	Loopstick Antenna (See Notes)
SPKR1	1	Crystal Earphone
MISC	1	Wire, Board, Wire For Antenna, Knob For C1

Notes

C1 and L1 can be bought, or salvaged from an old AM radio (which is where I got mine). You may need to experiment with the connections on L1 in order to get the best (or any) signal.

You may or may not need the ground connection. I never use it and the radio usually works fine without it.

The bigger the antenna, the more stations you pick up and the louder you hear them. On my radio, I get about 10 stations, 3 of which are very loud in the earphone. Of course, not everyone has room for a 60' antenna...

A 47K resistor in parallel with the earphone will help properly load the detector (This suggestion from Kb8tej1@aol.com)

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Comments

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razorradio Crystal Radio Friday, November 06, 2009 2:37:33 PM

This is a great hobby. One of my first xtal radios was this same circuit!. I even had a radio that was just a diode and an earpiece! If you live close to a radio station and have a good antenna and ground you will either get one station or several at once. My main crysatal radio when I was a kid was a variable loopstick + a 1N60 diode (similar to a 1N34) and a crystal earpiece. I also biult a couple radios that had a razorblade touched by a pencil lead as a detector instead of the diode. I recently just got my first DX on an AM crystal set. The circuit is similar to yours, but with a tapped coil on PVC pipe instead of a ferrite loopstick. NOTE TO NEWCOMERS: A regular earphone will not work. You need a crystal earphone (also called piezo electric).

arun Crystal Radio Thursday, October 15, 2009 6:04:48 AM

Is there any kind of inductor or rheostat is needed.......Loop stick anteena has only one terminal ..How to connect both +ve and ground ...Plzzzz reply soon

anonymous Crystal Radio Wednesday, September 02, 2009 9:16:41 AM

There is NO FM radios on that page.

anonymous Crystal Radio Wednesday, September 02, 2009 9:13:52 AM

Can a loudspeaker be used for the circuit instead of the crystal earphone????????

anonymous Crystal Radio Tuesday, July 21, 2009 4:59:35 AM

can we use this device to make light flickers by changing the speaker to LED

anonymous Crystal Radio Friday, May 08, 2009 8:20:19 PM

If this radio is able to use the energy from the radio waves interacting with the antenna coil for power, is there a way to use this as a free energy device too? Turn this into a small charger for example
(Editor's notes: We're only talking a few microamps here.)

Sanjeet Crystal Radio Sunday, February 15, 2009 3:56:23 AM

Where is the battery or power or it is of without battery?

alex Crystal Radio Saturday, January 31, 2009 3:23:15 PM

Crystal radio's require NO power source. they are able to use the energy from the radio waves interacting with the antenna coil. The germanium diode with it's low forward bias voltage is the ideal device for use in this circuit.

pranab Crystal Radio Saturday, January 31, 2009 3:27:43 AM

its not working properly

sumit Crystal Radio Friday, July 25, 2008 8:18:57 AM

where's the supply voltage?

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razorradio	Crystal Radio	Friday, November 06, 2009 2:37:33 PM
This is a great hobby. One of my first xtal radios was this same circuit!. I even had a radio that was just a diode and an earpiece! If you live close to a radio station and have a good antenna and ground you will either get one station or several at once. My main crysatal radio when I was a kid was a variable loopstick + a 1N60 diode (similar to a 1N34) and a crystal earpiece. I also biult a couple radios that had a razorblade touched by a pencil lead as a detector instead of the diode. I recently just got my first DX on an AM crystal set. The circuit is similar to yours, but with a tapped coil on PVC pipe instead of a ferrite loopstick. NOTE TO NEWCOMERS: A regular earphone will not work. You need a crystal earphone (also called piezo electric).
arun	Crystal Radio	Thursday, October 15, 2009 6:04:48 AM
Is there any kind of inductor or rheostat is needed.......Loop stick anteena has only one terminal ..How to connect both +ve and ground ...Plzzzz reply soon
anonymous	Crystal Radio	Wednesday, September 02, 2009 9:16:41 AM
There is NO FM radios on that page.
anonymous	Crystal Radio	Wednesday, September 02, 2009 9:13:52 AM
Can a loudspeaker be used for the circuit instead of the crystal earphone????????
anonymous	Crystal Radio	Tuesday, July 21, 2009 4:59:35 AM
can we use this device to make light flickers by changing the speaker to LED
anonymous	Crystal Radio	Friday, May 08, 2009 8:20:19 PM
If this radio is able to use the energy from the radio waves interacting with the antenna coil for power, is there a way to use this as a free energy device too? Turn this into a small charger for example (Editor's notes: We're only talking a few microamps here.)
Sanjeet	Crystal Radio	Sunday, February 15, 2009 3:56:23 AM
Where is the battery or power or it is of without battery?
alex	Crystal Radio	Saturday, January 31, 2009 3:23:15 PM
Crystal radio's require NO power source. they are able to use the energy from the radio waves interacting with the antenna coil. The germanium diode with it's low forward bias voltage is the ideal device for use in this circuit.
pranab	Crystal Radio	Saturday, January 31, 2009 3:27:43 AM
its not working properly
sumit	Crystal Radio	Friday, July 25, 2008 8:18:57 AM
where's the supply voltage?