 # What Resistor Do I Need For 3v Led?

## What resistor do I need to drop 12v to 3v?

Putting four resistors in serial and connecting it with 12V power source.

Taking voltage only from one resistor; thereby achieving 1/4 of power source from it.

take a 12v 4ohms potentiometer where the pointer will be adjusted at 3 ohms so that the voltage at last 1 ohm will be 3v..

## How do I reduce 5v to 1.5 V?

USB 5V to 1.5V Step Down Converter CircuitIn the circuit, we use LM317 DC voltage Regulator. To reduce the 5V input voltage from USB Port to the 1.5V at 1.5A maximum output.When we use a Cheap MP3 Player (or all Small Appliances). … If we take it to listen to music in the house. … We can use this circuit to convert 5VDC to 1.5VDC. … I used a popular IC – LM317.

## 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.

## How do I reduce 12v to 5v?

Convert 12V DC to 5V DCStep 1: Take All Components As Shown Below and in Pictures. Components required – … Step 2: Connect Input Power Supply. 7805 voltage regulator contain three pins.In which we have to give power supply on pin-1 and pin-2. … Step 3: Output Power Supply. … Step 4: Wiring Is Completed. … Step 5: Checking.

## Do resistors reduce voltage?

Resistors don’t reduce current and voltage instead it opposes flow of current and produce drop in voltage across the terminals.

## Can I use 12v for 5v?

Current is decided by Ohms law, I=V/R. With 12V your device will draw double the current and gets heated up because all current limiting values of your device are calculated for 5V source. … Most TTL ICs which are rated for 5V have a max acceptable voltage limit at 7V.

## Should resistor go before after LED?

It doesn’t matter! The resistor can go before – or after – the LED, and it will still protect it. You see.. the current that flows out of a battery is always equal to the current that flows back in to the battery. … The current through the resistor is the same as the current through the LED.

## Do SMD leds need resistors?

The general solution can be simple. If you choose Red or Yellow with a 3.3V drive signal on a 2V LED, you need a Resistor. If you choose Blue, white or green, you may not need a resistor. … Then look at a tiny SMD Green LED.

## What resistor do I need to drop 12v to 5v?

PLace two resistors in series with the 2nd resistor value (5/7) of the first resistor value. Place the resistors between 12v and ground and then you will get 5v at the point between them. This is a very crude way of doing it. It is unregulated so the voltage out will be dependent of voltage in.

## Does a 12v LED need a resistor?

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.

## Will a 12v LED run on a 9v?

No. The other posters are probably correct in that you probably could run the 12V LEDs from 9V, albeit at reduced brightness. But they are making an assumption about the wiring of the LED(s) in the light. … Three white LEDs in series are 9.6V before you add the current limiting resistor.

## 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.

## What resistor do I need for 5v LED?

Basics: Picking Resistors for LEDsPower Supply VoltageLED ColorResistor (rounded)5 VBlue, Green, White, or UV68 Ω5 VRed, Yellow, or Yellow-Green150 Ω5 VRed, Yellow, or Yellow-Green56 Ω9 VRed, Yellow, or Yellow-Green75 Ω4 more rows•Aug 29, 2012

## How do you reduce voltage from 12v to 5v with a resistor?

Connect 12 v to pin 1 ,pin 2 is the ground and pin3 gives 5v. Don’t want to use IC or not getting it,use a voltage divider using 2 resistors and you are done with it. Connect 12 v across the series combination of 4.7k ohm and 6.8k ohm(readily available standard ) resistor and take the output across 4.7k ohm.

## Why do you need a 330 ohm resistor for an LED?

330 ohms may be used by some people as a “get you going” value that works “well enough” in many cases. The purpose of the resistor is to “drop” voltage that is not required to operate the LED, when the LED is operating at the desired current.

## 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.

## What resistor do I need to drop 5v to 3v?

So back to our circuit, if we have 5 volts and want 3V from it, we use the formula above. If we use a 10KΩ as our R1 resistor, plugging in the values, we get R2= (V)(R1)/(VIN – V)= (3V)(10KΩ)/(5V – 3V)= 15KΩ. So we can use a 15KΩ resistor as our R2 resistor with the R1 resistor being 10KΩ. Let’s do one more example.

## 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.

## Do I need a resistor for LED?

Resistors in Light Emitting Diode (LED) Circuits 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 that it burns. If the voltage source is equal to the voltage drop of the LED, no resistor is required.

## 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.