Ohm's Law & Resistor Circuits Back
Electronics Calculator

Ohm's Law & Resistor Circuit Calculator

Enter any 2 of V, I, R to instantly solve for the third and compute power P. Analyze series and parallel resistor networks with live SVG diagrams.

Calculator Mode

Leave the unknown field blank and fill in the other two values.

Voltage V
V
Current I
A
Resistance R
Ω
Please enter exactly 2 positive values.
Voltage V [V]
Current I [A]
Resistance R [Ω]
Power P [W]
Calculation Detail

Theory

Ohm's Law:

$$V = IR \quad \Longleftrightarrow \quad I = \frac{V}{R} \quad \Longleftrightarrow \quad R = \frac{V}{I}$$

Power dissipation:

$$P = VI = I^2 R = \frac{V^2}{R}$$

Series: $R_{total} = R_1 + R_2 + \cdots + R_n$

Parallel: $\dfrac{1}{R_{total}} = \dfrac{1}{R_1} + \dfrac{1}{R_2} + \cdots + \dfrac{1}{R_n}$

CAE relevance: I²R losses in PCB traces and resistors feed directly into FEM thermal models as heat sources. Shunt resistor sizing, motor winding loss analysis, and connector contact resistance estimation all use Ohm's Law as the first-principles check before simulation. The parallel conductance formula is mathematically identical to the assembly of element conductance matrices in FEA.