Convert watts to ohms: find resistance from power and voltage or current, or work out watts from ohms and volts, for resistive DC or AC loads.
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Watts To Ohms Formula
For a resistive load, use R = Vยฒ/P when voltage is known, or R = P/Iยฒ when current is known. Use watts, volts, amperes and ohms; for purely resistive AC, use RMS voltage/current and average real power.
Variables:
- R is the electrical resistance (ohms)
- V is the voltage (volts)
- P is the power (watts)
To calculate the electrical resistance, square the voltage and then divide by the power. This will give you the resistance in ohms.
| Power (W) | Resistance (ฮฉ) |
|---|---|
| 0.25 | 576.000 |
| 0.5 | 288.000 |
| 1 | 144.000 |
| 2 | 72.000 |
| 3 | 48.000 |
| 5 | 28.800 |
| 7.5 | 19.200 |
| 10 | 14.400 |
| 12 | 12.000 |
| 15 | 9.600 |
| 20 | 7.200 |
| 25 | 5.760 |
| 30 | 4.800 |
| 40 | 3.600 |
| 50 | 2.880 |
| 60 | 2.400 |
| 75 | 1.920 |
| 100 | 1.440 |
| 150 | 0.960 |
| 200 | 0.720 |
| * Rounded to 3 decimals. Ohm’s law: R = Vยฒ / P. Assumes constant voltage V = 12 V DC. | |
What is Watts To Ohms?
Watts and ohms are units of measurement used in electrical systems. Watts measure the rate of energy conversion or transfer and are often used to quantify the output power of a system. Ohms, on the other hand, measure electrical resistance, indicating how much a device or material resists the flow of electric current. The relationship between these two units is defined by Ohm’s Law and the Power Law in electrical engineering, which states that power (in watts) equals voltage squared divided by resistance (in ohms). Therefore, “Watts to Ohms” typically refers to the process of calculating electrical resistance given power and voltage.
How to Calculate Watts To Ohms?
The following steps outline how to calculate the Watts To Ohms using the formula: R = V2 / P.
- First, determine the voltage (V) in volts.
- Next, determine the power (P) in watts.
- Next, use the formula R = V2 / P to calculate the electrical resistance (R) in ohms.
- For the current-based mode, select Resistance from watts and amps, enter power and current, then select Calculate.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
voltage (V) = 12 volts
power (P) = 36 watts. The resistance is 12ยฒ รท 36 = 4 ฮฉ, and the current is 36 รท 12 = 3 A.
