# OHM's Law

## Quick Reference​

### Ohm's Law Calculations​

V = I * RR = V / II = V / R

### Power Triangle​

The amount of current flowing through a conductor is proportional to the voltage applied across the conductor. This is true of all conductors with the exception of super-conductors. Mathematically this is stated as:

V = k * I

Where:

• V is the voltage (in volts) drop across the conductor.
• I (for Intensity), the current (in amps) flowing through the conductor.
• k is the constant of proportionality.

### Ohm's Law​

This relation is codified in Ohm's Law, where, k is replaced by resistance (in ohms) of the conductor. The equation becomes:

V = I * R

For historical reasons, amperage is often labeled I (for intensity), and sometimes voltage is labeled E (for electromotive force). So, while the most common labeling for Ohm's law is typically uses V for volts, I for amps, and R for resistance, sometimes the following is seen:

E = I * R

Where E is voltage.

### Other Forms of Ohm's Law​

Using algebra, Ohm's law can also be solved for resistance (R) or (I):

#### Solved for Resistance (R)​

R = V / Iohms = volts / amps

#### Solved for Voltage (V)​

I = V / Ramps = volts / ohms

### Ohm's Law Pyramid​

The Ohm's Law triangle, also known as the power triangle is helpful in remembering the various solutions of Ohm's law:

It roughly represents the mathematical relationship of Ohm's law; it's divided vertically by a line that indicates division (below V), and horizontally, with a line that stands for multiplication (between I and R).

To read it, choose any given unit as the solution, and then use the division/multiplication rules of the lines.

Therefore, starting with a solution for V, it's read as:

V = I * R