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

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.

**Why do you need a 220 resistor in series with the LED?**

You use a resistor in series with the LED to keep it from receiving too much voltage. Without the resistor, the LED would be brighter for a few moments, but quickly burn out.

### What size resistor should I use with an LED?

LEDs typically require 10 to 20mA, the datasheet for the LED will detail this along with the forward voltage drop. For example an ultra bright blue LED with a 9V battery has a forward voltage of 3.2V and typical current of 20mA. So the resistor needs to be 290 ohms or as close as is available.

**How many ohms is a 220 resistor?**

Specifications

Specification | Value |
---|---|

Resistance (Ohm) | 220 |

Tolerance | 5% |

Composition | Carbon Film |

Size | Standard |

## How many LED can a 12v power?

You can use as many branches of 3 leds as the power supply can power.

**How do I connect LED to 12v DC?**

Connect the positive terminal of the 12 volt power supply to one side of the resistor. Connect the other side of the resistor to the anode of the LED. Check the LED data sheet to identify the anode and cathode. The cathode is commonly the shorter lead and located nearest any flat side of the LED.

### Why do you put a resistor before an LED?

An LED (Light Emitting Diode) emits light when an electric current passes through it. The ballast resistor is used to limit the current through the LED and to prevent excess current that can burn out the LED. If the voltage source is equal to the voltage drop of the LED, no resistor is required.

**What resistor do I need to reduce voltage?**

To reduce voltage in half, we simply form a voltage divider circuit between 2 resistors of equal value (for example, 2 10KΩ) resistors. To divide voltage in half, all you must do is place any 2 resistors of equal value in series and then place a jumper wire in between the resistors.

## What resistor do I need to drop 12V to 9V?

To reduce a 12V circuit to 9V, place two resistors in series within the circuit. Find the difference between the two voltages (12V – 9V = 3V) to determine the total amount of resistance needed.

**What size resistor do I need for 12 volt LED lights?**

the resistor until I get 20 mA. For 12 Volts, this usually works out to be a 470 Ohm resistor, which is the value I use for my LED light chaser strings. Here’s an example of current measurements I made using 12 Volts and 470 Ohm resistors, according to the LED color. As you can see, 470

### What is the resistor value for a 5 volt led?

For 5 Volt operation, my resistor value of choice is 150 Ohms. For a red LED, the current is pretty close to 20 mA, but for a blue one, it is more like 10 mA. The lower voltage makes it more difficult to maintain the same current through different color LEDs than is possible at 12 Volt operation.

**How do I calculate the resistor needed for a simple LED circuit?**

To calculate the resistor needed for a simple LED circuit, simply take the voltage drop away from the source voltage then apply Ohm’s Law. In other words… R is the resistance, measured in Ohms (Ω).

## How do you calculate the resistance of a 12 volt resistor?

Resistor = (Battery Voltage – LED voltage) / desired LED current. So assuming a 12 volt power source and a white LED with a desired current of 10 mA; The formula becomes Resistor = (12-3.4)/.010 which is 860 ohms. Since this is not a standard value I would use an 820 ohm resistor.