# Quick Answer: Do LEDs Have Resistance?

## Do LEDs have internal resistance?

The long answer: LEDs are semiconductors, diodes in particular.

Current versus voltage is a straight line for a resistor, but not at all for an LED.

Because of this, you can’t say that LEDs have “resistance.” Resistance is defined as the constant ratio of voltage to current in a resistive circuit element..

## Do LEDs fail open or short?

4 Answers. LEDs that fail catastrophically usually fail open circuit but some occasionally fail short circuit. Large groups of LEDs are often arranged as say X strings of Y LEDs in series in each string.

## Do I need a resistor for each LED?

The simplest circuit to power an LED is a voltage source with a resistor and an LED in series. … The ballast resistor is used to limit the current through the LED and to prevent that it burns. If the voltage source is equal to the voltage drop of the LED, no resistor is required.

## Do I need a resistor for a 12v LED?

Originally Answered: In order to light an LED with a 12V, what resistor value is needed? Normally, you want to minimize waste, so you connect as many LED in series as possible to consume the voltage provided, then you use a resistor to limit the current to the correct value. White LEDs are universally using 3.0 volts.

## Can I connect led without resistor?

Never Ever Connect an LED Without a Resistor, Mostly. When hooking up an LED, you are always supposed to use a current-limiting resistor to protect the LED from the full voltage.

## What is the resistance of a LED light?

Basics: Picking Resistors for LEDsPower Supply VoltageLED ColorResistor (calculated)5 VBlue, Green, White, or UV68 Ω5 VRed, Yellow, or Yellow-Green128 Ω5 VRed, Yellow, or Yellow-Green56 Ω9 VRed, Yellow, or Yellow-Green72 Ω4 more rows•Aug 29, 2012

## What happens if you don’t use a resistor with an LED?

If you don’t put a resistor in series with the LED and you apply power, the current through the LED will exceed its rating and it will be destroyed. You can use the following equation to solve for R. Vdiode is the diode’s forward turn on voltage.

## How many LEDs can be connected in parallel?

Wiring LEDs in parallel allows many LEDs to share just one low voltage power supply. We could take those same four 3V LEDs and wire them in parallel to a smaller power supply, say two AA batteries putting out a total of 3V and each of the LEDs would get the 3V they need.

## Can I connect a LED directly to a battery?

Powering an LED is not as easy as simply hooking it up to a battery. An LED has almost no internal resistance. Therefore, if you hook it up directly to a battery, it will burn out quickly as the current flows unimpeded through the LED. You must add a resistor to the LED circuit.

## Do you need a special flasher for LED lights?

The reason most mechanical flashers won’t work with LEDs is that they require very little current flow, which is not enough to heat the internal strip and open the circuit. There are several types of electronic flashers available, however, not all of them are for LED applications.

## How do I know what resistor to use with LED?

Determine the voltage and current needed for your LED. We’ll use the following formula to determine the resistor value: Resistor = (Battery Voltage – LED voltage) / desired LED current. For a typical white LED that requires 10mA, powered by 12V the values are: (12-3.4)/. 010=860 ohms.