I know this suppose to be an easy solution but for some reason I can't get my head around it. I'm experimenting with simple LED with breadboard this is what I have.
1. Breadboard (solderless board)
2. 12v (6 x 1.5v) battery holder.
3. LED (this is the LED specification -> **broken link removed**)
I tried using resistor of 0.25w it blew up (both the LED and the resistor), next I tried resistor of 0.5w the LED glows a bit and then it dies off looks like it got burnt or something, next I tried 1W resistor it's the same like the
0.5w, I'm not sure what is wrong. Can anybody help me to point me in the right direction ?
you have to use a resistor in series with the LED , the value of the resistor varies with the led colour , this is to reduce current in the circuit to protect LED , see below page Resistor value calucations for LEDs
These are the 2 resistors that I mentioned in my previous thread the one with paper cover that says 'SOANAR' it says it's 1W while the other one it mentioned in the plastic it's 0.5W
Looks like after using one of BigDog's link I managed to calculate the Ω values which comes to - 10 and 15 which makes sense why the LED keep on blowing up. Need to go back to electronic shop to do more resistor shopping.
Hi Nick, the pakage says 15 ohms; thats WAY too low! As per you LED specs, it drops 2 volts across itself; you have a supply of 9 volts. So, assuming you want to drive the LED at 20 ma, you need a resistor of around 470 ohms. The wattage of the resistor is fine; for these values even a 1/4 watt should do.
If you examine the two labels shown in the photos you provided, you will notice they indicate 10R and 15R which is equivalent to 10Ω and 15Ω, the use of R to represent ohms stems from the lack of the omega (Ω) character in some label fonts.