how do you power LEDs?
09-25-2002, 09:36 AM
#5
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you'll need resistors..
that particuluar LED you pictured, is a dual color LED... the cathode (-) is always the short lead(s) and the anode (+) is the longer lead(s)...
LED's usually work on about 1.5 to 1.7 volts... so you need a resistor to step the 12 volts down to roughly 1.7 volts.
To find the resistor you need, heres a simple formula using 1.7 volts.
Incomming voltage - voltage required
.02 Amps
=resistance of resistor
so you'd need to do:
12 - 1.7
.02
to get 515ohms, this is the size of the resistor needed... or anything very close to its resistance.
If you go to radio shack, they have a bunch of different resistors, depending on how many you connect, determines the wattage of the resistor... for a single LED, i'd recomend 1/2 watt resistors...
so you want 1/2 watt, 515ohm (roughly) resistors... they come in a pack of 5 for $.99
that particuluar LED you pictured, is a dual color LED... the cathode (-) is always the short lead(s) and the anode (+) is the longer lead(s)...
LED's usually work on about 1.5 to 1.7 volts... so you need a resistor to step the 12 volts down to roughly 1.7 volts.
To find the resistor you need, heres a simple formula using 1.7 volts.
Incomming voltage - voltage required
.02 Amps
=resistance of resistor
so you'd need to do:
12 - 1.7
.02
to get 515ohms, this is the size of the resistor needed... or anything very close to its resistance.
If you go to radio shack, they have a bunch of different resistors, depending on how many you connect, determines the wattage of the resistor... for a single LED, i'd recomend 1/2 watt resistors...
so you want 1/2 watt, 515ohm (roughly) resistors... they come in a pack of 5 for $.99
09-25-2002, 03:38 PM
#7
More Black on Black Crime
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Originally posted by steveng
why not get scanner type instead of LED? scanner is easier to install which no drill is needed and it's cheaper too
why not get scanner type instead of LED? scanner is easier to install which no drill is needed and it's cheaper too
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