# Do all LED lights need a resistor?

Contents

An LED (Light Emitting Diode) emits light when an electric current passes through it. The simplest circuit to power an LED is a voltage source with a resistor and an LED in series. Such a resistor is often called a ballast resistor. … If the voltage source is equal to the voltage drop of the LED, no resistor is required.

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

When hooking up an LED, you are always supposed to use a current-limiting resistor to protect the LED from the full voltage. If you hook the LED up directly to the 5 volts without a resistor, the LED will be over-driven, it will be very bright for a while, and then it will burn out.

## Do you need load resistor for LED lights?

On an indicator light circuit, the fault appears as a fast flash.To overcome it, it is necessary to fit a load resistor that matches the original light globe wattage at the same time as the LED lights are fitted. Resistors used in this manner, however, are an inefficient use of energy.

IT IS INTERESTING:  Best answer: How good are Cree LED lights?

## What happens if there is no resistor?

a) If there is no resistor in the circuit ( as in , if you completely remove the resistor) , then there will be no current flowing in the circuit. However, there will be a voltage at the 2 terminal points where the removed resistor used to be.

## What resistance should I use for LED?

Basics: Picking Resistors for LEDs

Power Supply Voltage LED Color Resistor (rounded)
3 V Red, Yellow, or Yellow-Green 51 Ω
4.5 V Red, Yellow, or Yellow-Green 39 Ω
4.5 V Blue, Green, White, or UV 51 Ω
5 V Blue, Green, White, or UV 68 Ω

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

1 Answer. AFAIK there is no, or at least no common, led diode that is typically 12V forward voltage by it self. 12V led are modules that consist of some combination of diodes and resistors to make them suitable for 12V power applications without needing extra current limiting.

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

Never connect an LED directly to a battery or power supply because the LED is likely to be destroyed by excessive current passing through it. resistor is suitable for most LEDs if your supply voltage is 12V or less.

## What resistor do I need for 12V LED?

Originally Answered: In order to light an LED with a 12V, what resistor value is needed? LEDs are forward biased for light emitting, In forward bias the resistance value will be less. typically 10 Ohms to maximum 100 0hms. For safe calculation you may take 50 ohms.

## How many LED load resistors do I need?

If the same circuit wire is feeding into the two bulbs on each side of the truck, you should only need one resistor on each side, in-line with the circuit before the bulb (for a total of two).

IT IS INTERESTING:  Do snakes like LED lights?

## How do you know if a resistor is ohmic?

A resistor is ‘Ohmic’ if as voltage across the resistor is increased, a graph of voltage versus current shows a straight line (indicating a constant resistance). The slope of the line is the value of the resistance. A resistor is ‘non-Ohmic’ if the graph of voltage versus current is not a straight line.

## Do you need a resistor in a circuit?

Resistors are needed to set currents and adjust voltage levels through a series circuit. They are used for other functions too, like part of frequency filters, oscillators etc. etc.

## Can you have voltage without resistance?

Voltage can certainly exist without resistance. If you have an electric field in empty space (or, for example, in a capacitor) there will be a potential difference even though there are no resistors around. … In the first case (no path for electrons to flow) then yes, voltage can exist.

## How do I know what resistor to use with 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. To use several LEDs in parallel, sum the current values.

## Where does the resistor go on a LED?

Since this resistor is only being used to limit current through the circuit, it can actually be located on either side of the LED. Placing the resistor on the positive (anode) side of the resistor will have no differing effects from placing the resistor on the negative (cathode) side of the LED.

IT IS INTERESTING:  You asked: Do LED bulbs have gas in them?

## What happens if a high voltage is connected to an LED directly?

The voltage drops across all of these resistors plus the LED’s intrinsic voltage drop will add up to the battery voltage. The only question is: At what current does this happen? If it is high enough your LED will cook and burn up.