View Full Version : voltage / current / resistor question
TerenceT 08-23-2003, 03:46 AM voltage equals current time resistance
V = I R
so i am going to get some LEDs for interior lighting that are
1.7vdc to 2.2 vdc
car voltage is 14 vdc to 12 vdc
so
(14vdc - 1.95vdc) / .035 = 344.3 ohms
??
ozbot87 08-23-2003, 11:20 PM Yup.
BTW, what kind of LEDs are you getting? (Electrical Engineer here, so you can give me detailed info about them. :D )
TerenceT 08-24-2003, 02:23 AM let's look at my shopping list...
interior dome light, front(2) and back(2), and passanger foot well (2)
10 red LEDs 2200mcd, 5mm, clear, 45 degree, 1.7-2.2 vcd, 20ma
exterior mirrors bottom, going to tap the door light, so they'll come on when i hit the remote
2 yellow, 1200mcd, 5mm, clear, 45 degree, 1.7-2.2 vcd, 20ma
Misc
1/2 watt, flame proof 10 ohm resistors
1/2 watt, flame proof 330 ohm resistors
was going to get diodes but give up finding them
TerenceT 08-24-2003, 02:31 AM let's look at my shopping list...
interior dome light, front(2) and back(2), and passanger foot well (2)
10 red LEDs 2200mcd, 5mm, clear, 45 degree, 1.7-2.2 vcd, 20ma
exterior mirrors bottom, going to tap the door light, so they'll come on when i hit the remote
2 yellow, 1200mcd, 5mm, clear, 45 degree, 1.7-2.2 vcd, 20ma
Misc
1/2 watt, flame proof 10 ohm resistors
1/2 watt, flame proof 330 ohm resistors
was going to get diodes but give up finding them
ozbot87 08-24-2003, 03:04 AM Good place to get parts such as diodes are:
Digi-Key.com
Or if you are a student, you can try to get samples from:
fairchildsemi.com
lite-on.com.tw
There are other LED manufacturers out there who might give you samples depending on the field of work you are in.
Hope this helps.
TerenceT 08-24-2003, 03:13 AM thanks man
i'll keep the links but from partsexpress.com
the bill comes out to be 10 bucks plus shipping
note to others:
LEDs are not as expensive as people might think!
Doctorr 08-24-2003, 03:14 AM Just bought 50 of the little b*ggers off ebay, for the footwell project......
12,000mcd.......SHOULD be bright enough......
Not very good with the cut&paste stuff, but the item # was 2550748679......also explains why I bought 50, when the lot size was 25......hit the 'buy now' button twice!.....DOH!
.
.
.
doc
TerenceT 08-24-2003, 03:21 AM the one you bought are very very bright!!
and focus too, only 6 degree
you'll be able to see if you date shave her legs!!! thru her panty hose!!1
Doctorr 08-24-2003, 03:26 AM I think your math is fine - 330 Ohms will be perfect.
You should consider bundling a few together, since they are so small, and the mirror is a long way from the ground.....
Keep us posted!
.
.
.
doc
|
|