[TechAssist] Re: |Can LEDs be used in place of fuse lamps - see prev question
- From: "J Silverman" <greentron@xxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 20 Nov 2002 18:02:40 -0500
The LEDS are like forward biased diodes that have a 1 volt drop and require
a resistor to limit the current, usually to about 25 ma. You would have to
put a shunt resistor across the combination to draw the rest of the current.
If the power source is AC, the LED would be reverse biased for half the
cycle. LEDs wont take more than 5 volts of reverse bias without breaking
down, so you need to protect the LED by connecting a diode across it to
coduct on the half cycle when the LED is reverse biased. Another option is
to use another LED instead of a diode. Still another option is to put the
LED in a full wave bridge rectifier circuit.
The series resistor for the 12 volt LED should be 470 ohms and the shunt
should be 47 ohms, 3 watt. The series resistor for the 6 volt circuit should
be 220 ohms and the shunt should be 4 ohms, 10 watt.
Jerry Silverman
Greentron Inc
4 Newland Ave
Greenville SC 29609
864 232 3889
Fax 271 2080
mailto:greentron@xxxxxxx
----- Original Message -----
From: "babalino" <babalino@xxxxxxxxxxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, November 20, 2002 5:30 PM
Subject: [TechAssist] |Can LEDs be used in place of fuse lamps - see prev
question
>
> Can leds be used in place of these lamps - any special considerations if
> this is the case?
>
> PREVIOUS QUESTION WAS:
>
> I have a problem with a "fairly old" amplifier (Realistic STA-16B) It has
> 8
> > ohm speakers and 150W output. The four 'light
> display "fuses?"' are blown. (will not work without these). They are (X3)
> 12V, in
> > series, at 0.25A and one at 6V at 1.5A. They are 30mm in length and are
> > glass fuses - nothing else written on them. Any help where I can get
> > replacements. I know it is a bit of a long-winded question but would
> really
> > appreciate some help here.
> > Thanks again babalino
>
> Mr D Graham
> Grahams Electronics
> 978 Walker Road
> Newcastle upon Tyne
> England
>
>
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