multi colored led lights

[mike03]

What resistor should i use for a single multi colored led lights and how much volt to apply without burning the led?

 

[Vizier87]

the right way to identify LED ratings is to know it's maximum current rating. Chinese models withstand lower current/voltages as opposed to the standard ones. If you have a full supply of 5V output from a 7805 a 670Ω resistor is optimal, but if you just want it to be noticeable you can even use 10K. It's up to you, given the range.

 

[AllVol]

What resistor should i use for a single multi colored led lights and how much volt to apply without burning the led?

It isn't voltage necessarily that burns LEDs, but over-current. That's why a limiting resistor is used in all LED circuits as a rule.

Generally speaking, most LEDs want less that 20 milliAmps of current, and 10 milliAmps is a good safe number. Use Ohm's Law to figure the resistor based on initial voltage less forward voltage of the LED divided by .010. Hint: it will usually be in the hundreds of ohms.