Ohm's Law Calculator
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Understanding Ohm's Law
Ohm's Law is a fundamental principle in electrical engineering that describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. The law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them.
The Basic Formula
V = I × R
Where:
- V = Voltage in volts (V)
- I = Current in amperes (A)
- R = Resistance in ohms (Ω)
From this basic formula, we can derive two other formulas:
I = V ÷ R
Current equals voltage divided by resistance
R = V ÷ I
Resistance equals voltage divided by current
Power Calculation
P = V × I
Where:
- P = Power in watts (W)
- V = Voltage in volts (V)
- I = Current in amperes (A)
We can also express power in terms of voltage and resistance or current and resistance:
P = V² ÷ R
Power equals voltage squared divided by resistance
P = I² × R
Power equals current squared times resistance
The Ohm's Law Triangle
A common way to remember the relationship between voltage, current, and resistance is the Ohm's Law triangle. By covering the variable you want to find, the triangle shows you how to calculate it using the other two variables.
Applications of Ohm's Law
Ohm's Law is used in a wide range of electrical applications, including:
- Designing and analyzing electrical circuits
- Troubleshooting electrical problems
- Calculating power consumption
- Sizing components like resistors, fuses, and wires
- Determining battery life and performance
Limitations of Ohm's Law
While Ohm's Law is a fundamental principle, it's important to note that it applies only to ohmic conductors (like most metals) at constant temperature. Non-ohmic components like diodes, transistors, and thermistors do not follow Ohm's Law under all conditions.