Users' questions

What is the resistance of a 12 volt bulb?

What is the resistance of a 12 volt bulb?

Each incandescent bulb (12-volt/system) measures 1.5 ohms with a meter; however, there is no resistance across the LED [replacement] bulbs.

What is the resistance of a 12v 5w bulb?

I think that the resistors that are shown in the original link are for side light bulbs which are 5w, which at 12v give a resistance of approx 30 ohms.

What is the resistance of a 12v 21W bulb?

21W Bulb: R = 144/21 => 7 Ohms (rounding up). If you have wired the turn signal to the parking light then you shouldn’t get an error (the parking light is assuming a resistance of less than 28.8 Ohms is a blown bulb).

How do you test a 12 volt lamp?

Steps for Testing the Bulb

  1. Set your multimeter: Begin by turning the dial on your multimeter to the “ohms” setting.
  2. Test your multimeter: Touch the two probes of your multimeter together.
  3. Connect the pins: The multimeter will have two small test probes, which you can touch to the light bulb to get a reading.

Do you need a resistor for a 12V led?

You give too little information for a definitive answer. If this is a “12V” LED, which generally will consist of several LED chips in combination, no resistor is required. These are often supplied as replacements for automotive light bulbs such as the “festoon” type used as the interior light in a car.

Why does a 12 volt circuit have a higher current?

Ohm’s Law – states the relation ship of Voltage to Current & Resistance: For a given power requirement, a higher voltage will require fewer amps and vice versa. This is the reason that circuits operating at 12V DC can produce much higher currents than would be experienced in household AC circuits that operate at 240V AC.

What is the current draw of a 12 volt light?

So for example, if we wanted to wire up a light that we know has a power rating of 50W, then the current draw would be 50W/12V = 4.17A.

How much power do you need for a 12V led?

Another requirement is to determine the power so that the resistor can withstand the current. Using your 12 volt source. With various LEDs with forward voltages (Vf) of 1.85 to 3.2 volts the power requirement ranges from 225 to 239 mW using the nearest higher resistor from the standard 5% range of resistors.

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