a diagram or a webpage of some sort just to study
2007-02-10 09:09:29 · 4 answers · asked by twohitsmf 1 in Science & Mathematics ➔ Engineering
If you connect a LED directly to a battery, it will probably burn out since there will be nothing that limits the current flowing through the LED. LEDs cannot tolerate unlimited current flow.
The usual way to limit the current to an acceptable level is to put a resistor between one of the LED's connections ot the battery. Here's a site that explains how to do this (see the section "Calculating an LED resistor value")
2007-02-10 09:26:03 · answer #1 · answered by polyglot_1234 3 · 2⤊ 0⤋
Most leds work on 1.2 volts at around 10mA of current.
Take away 1.2 volts away from battery voltage, divide your answer by 0.01, the result is the value of your resistor in Ohms
eg if battery is 9v
than 9-1.2=7.8
Resistor=7.8/0.01
R=780 Ohms
Current can vary from 5 to 20 mA but dont exceed 20mA.Some bright leds can have a higher working voltage at around 3v.
2007-02-11 01:38:28 · answer #2 · answered by Anonymous · 1⤊ 0⤋
The can be directly connected to a battery if they are for the same voltage. The polarity must be correct. That is all.
I had one of those lit magnifying cards where the lens was no good. I took it apart and all there was was a led, battery, and a switch.
2007-02-10 17:13:42 · answer #3 · answered by Barkley Hound 7 · 1⤊ 1⤋
Polyglot's link is good.
You might also find this of help http://www.davidbridgen.com/leds.htm
2007-02-10 23:57:06 · answer #4 · answered by dmb06851 7 · 0⤊ 1⤋