From: John Woodgate
Subject: Re: Crystal radio
Date: Sat, 28 Sep 2002 22:48:30 +0100
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Sun, 29 Sep 2002 07:36:35 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that Leeper wrote
(in ) about 'Crystal radio', on Sat, 28
>I've got a nephew I'd like to show how to build a crystal set, like I did 30
>Anyhow, does anyone know where to get the high impedance crystal earphone?
Crystal earphones are not very sensitive. You'll be lucky to hear
anything unless you have an AM station very close.
AFAIK high-impedance magnetic headphones ( 2 to 4 kohm) are not made any
more. I happened to find a pair quite recently, in good condition in
spite of being over 50 years old.
>How about a source for the venerable 1N34A or any other better device
>recommendations these days?
Ge diodes are still available, but a low-power Schottky diode is nearly
>Looking to do the typical crystal set, that doesn't utilize a battery, just
>a wire antenna, coil, capacitor, diode and earphone.
Sure. There are at least two web sites that dal with nothing but crystal
receivers. I don't have the URLs but a Google search found them easily.
For your next project, you need a diaphragm or rocking-armature earphone
and a carbon microphone. Connect their diaphragms with a short, rigid
rod. Feed the earphone from the crystal set and put the microphone in
series with a 3 V battery and a loudspeaker. Amplification without tubes
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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