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From: firstname.lastname@example.org (Andre)
Subject: Re: RF drives LED ?
Date: 6 Jan 2003 00:54:35 -0800
NNTP-Posting-Date: 6 Jan 2003 08:54:35 GMT
email@example.com (Budiman) wrote in message news:...
> I just buy an 'anti electromagnetic radiation led' for my handphone.
> The led will flashing when there is a call to my handphone.
> The 'anti radiation led' has 2 leds (smd) and one unknown component
> (smd - three pins, a transistor ?) and no batery.
Yes, basically you have a rectifier in there to convert the AC from
the phone into DC to drive the LEDs (they don't like reverse voltage
> I think the circuit converts the RF into current to drives the LED.
> Does anyone have similiar circuit ?
Get a scrapped AM radio, swipe the glass diode (germanium) out of it .
It looks clear, like glass with a little wire inside (point contact)
going to the crystal. Voltage drop is .2 to .4 V
You might also try using a standard 1N4148 diode if you can't get
Solder an LED across the diode, with the leads sticking out to the
sides . Ensure that the germanium diode is soldered anode to LED
cathode, or else it won't light ! (on most LEDs, cathode is the "flat"
side of the package, and on most diodes the anode is the part without
the black band)
Use an RS red or orange LED, high brightness .
Take care not to break the diode or LED when soldering.
> I need the schematic.
> Thank you
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