What Is The Resistance Of A 12 Volt 21 Watt Bulb

I am pretty sure my meter is giving me the correct reading and that i am using it correctly.

What is the resistance of a 12 volt 21 watt bulb.

For example find the amperage of a 100 watt light bulb at 120 volts. V voltage i amperage x r resistance ohms however volt amps are equivalent to watts so r v i 12 24 0 5ohms. For example a 100 watt light bulb operating on 120 volts ac will have 144 ohms of resistance and will draw 0 833 amps. In theory the formula v ir i is current 12 55 or approximately 0 2 ohms.

V v i a r ω. Enter 100 in the watts field and 120 in the voltage field and press calculate to find the resistance and current. But in reality the resistance probably will go to infinity as that much current would almost certainly blow the filament. For example let s find the current of a 12 volt circuit with 10 ohms of resistance.

When they are placed in series the total resistance is about 500 w so each bulb sees a current of 120 500 0 24 a. Simple to use ohm s law calculator. Convert volts to amps using resistance. Calculate power current voltage or resistance.

Use a power equation to find the power for each bulb when they re in series with one another. Voltage e current i resistance r. These differ from the first set by a factor of 10. The voltage v in volts v is equal to the current i in amps a times the resistance r in ohms ω.

The power p in watts w is equal to the voltage v in volts v times the current i in amps a. Amps watts volts amps 100 w 120 v amps 83 a. Fields should be reset to 0 before each new calculation. The resistance r in ohms ω is equal to the squared voltage v in volts v divided by the power p in watts w.

Just enter 2 known values and the calculator will solve for the others. Before clicking in each ohm s law calculator for the answer enter numbers into the equation you wish to use to calculate for current power resistance or voltage. Amps volts ohms. The resistance r in ohms ω is equal to the power p in watts w divided by the squared current i in amps a.

P i 2 r 0 24 2 144 8 w. For the 100 watt bulb. Updated january 8 2011 to accept change commas to periods for those that use commas as decimal separators. You have to know the amperage.

5 watt bulb 2 9 ohms 6 watt bulb 2 1 ohms 10 watt bulb 1 8 ohms.