A heater of resistance 10 ohms draws 10 a current the electric power it consumes is

Calculate voltage/current/resistance/power.

Enter 2 values to get the other values and press the Calculate button:

• Ohm's law with examples
• Voltage divider
• Watts to amps

Ohm's law calculation formula

The current I in amps (A) is equal to the voltage V in volts (V) divided by the resistance R in ohms (Ω):

I = V / R

Example

I = 20V / 10Ω = 2A

The power P in watts (W) is equal to the voltage V in volts (V) times the current I in amps (A):

P = V × I

Example

P = 20V × 2A = 40W

Enter 2 values of magnitude+phase angle to get the other values and press the Calculate button:

AC Ohm's law calculation formula

The voltage V in volts (V) is eqaul to the current I in amps (A) times the impedance Z in ohms (Ω):

V(V) = I(A) × Z(Ω) = (|I|×|Z|) ∠ (θI + θZ)

The complex power S in volt-amps (VA):

S(VA) = (|V|×|I|) ∠ (θV - θI)

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Please provide any 2 values and click "Calculate" to get the other values in the ohm's law equations V = I × R and P = V × I.

Ohm's Law

Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage. This is true for many materials, over a wide range of voltages and currents, and the resistance and conductance of electronic components made from these materials remain constant. Ohm's Law is true for circuits that contain only resistive elements (no capacitors or inductors), regardless of whether the driving voltage or current is constant (DC) or time-varying (AC). It can be expressed using a number of equations, usually all three together, as shown below.

Where:

V is voltage in Volts R is resistance in Ohms

I is current in Amperes

Electrical Power

Power is the rate at which electrical energy is transferred by an electric circuit per unit time typically expressed in the SI (International System of Units) unit of Watts. Power is typically produced by electric generators and supplied to businesses and homes through the electric power industry, but can also be supplied by electric batteries or other sources.

In resistive circuits, Joule's Law can be combined with Ohm's Law to produce alternative expressions for the amount of power dissipated, as shown below.

Where:

P is power in Watts

Ohm's Law Formula Wheel

Below is a formula wheel for Ohm's Law relationships between P, I, V, and R. This is essentially what the calculator does, and is just a representation of the algebraic manipulation of the equations above. To use the wheel, choose the variable to solve for in the middle of the wheel, then use the relationship for the two known variables within the cross section of the circle.