[simpits-tech] Resistor for LEDs?

[Ben Jones]

Guys,

Can i suggest from a electrical background , not using your computer power
supply to power led's and there associated resistors,
for the simple factor that if you have a "misfortune" with a led or
associated wiring having a blow out or melt down , this could cause the
power supply to your pc to either fail or cause dammage to the boards if a
spike was created.

the power supplys being load dependant will constantly vary the amperage tho
maintain a constant voltage, if there was any big load changes on the supply
there is a chance that your led's will vary in light intensity being given
off..

My suggestion to solve this problem ( or anticipated problem) is to have a
separate filtered and proctected powersupply being of 12 v dc , supplying
your leds by a 12 v bus ( a parallel circuit)  , this is easy to tap off the
12 v needed take the active through your switched contact to turn the led
off and on , then through the  power dissapation resistor  onto the led and
out to  the 12v bus neutral,  because this is all in parallel  only the 1
wattage resistor is needed for each led , and because the supply is constant
where ever you tapp off ( given the powersupply can handle the full load
plus 10%) there should be no drop in intensity throught each led , as would
the cas be in a series circuit.

The only reason i suggest this is because the power supply is feeding some
pretty expensive gear and it works best just powering the computer, which is
the way it was designed for.

If there is any electronic techo's out there please correct me if i'm
wrong..

regards

ben

****************************
bjones@pipecomp.com.au
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----- Original Message -----
From: "Joseph Fagner" <crease-guard@attbi.com>

> That's simple, don't really need to know the load, just use an free
> molex connector from one of the systems running your simulator.  Your
> computer will provide the load.