HiTech Computers
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=56667
Printed Date: July 03, 2025 at 2:39 PM
Topic: HiTech Computers
Posted By: markob85
Subject: HiTech Computers
Date Posted: May 30, 2005 at 6:13 AM
I don't know how to conect more leds(two) on the computer. I use 5Volts supply, and I must use resistor to conect LED(3 Volts). Which resistor to use? Led is same as led on the front side of the computer (HDD,PWR).
5V+resistor?=3V. ??????????????????
Replies:
Posted By: ff-mike
Date Posted: June 01, 2005 at 11:24 AM
Besides the LED voltage, we need to know the current specs. Plug them into Ohms law (in your case R=E/I) to get your resistor size. Typical LEDs run about 25mA so you would have
R= (5-3)/.025
R= 80 Ohms
Not a common size, closest is 100 Ohms. This would give you 20mA drive, and you should be fine.
Something else you could do would be to get the same size resistor that is already in use on the computer
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