Electricity, Work, and Power

This online calculator can help you solve the problems on work done by the current and electric power. It can calculate current, voltage, resistance, work, power and time depending on what variables are known and what are unknown

This online calculator can be used to check the solution of problems for electric power and electrical work. To use it, simply enter known values and leave unknown values blank. If there are enough data, hit "Calculate" button and the calculator finds all unknowns

Sample problem: The crane consumes a current of 40A from an electrical network with a voltage of 380V. The crane took 3.5 minutes to lift the concrete slab. Find the work that the crane did.

To get the solution enter 40 into "Current" field, then enter 380 into "Voltage" field, then 3.5 into "Time" field, switching time units to "minutes". After that click "Calculate" button. The calculator outputs work in Joules, as well as power in Watts and resistance in Ohms (because it can). Formulas used for calculations can be found below the calculator.

PLANETCALC, Electricity, Work, and Power

Electricity, Work, and Power

Digits after the decimal point: 2
Current, Amps
Voltage, Volts
Resistance, Ohms
Work, Joules
Power, Watts
Time, seconds

Electrical work and power of electric current

Electrical work is the work done on an electric charge by electric force. Electric work can be found as the multiplication of quantity of transferred electric charge by electric potential or voltage between endpoints.

A = \Delta q U

From the other side, electric current is the rate of flow of electric charge past a point over time

I = \frac { \Delta q } { \Delta t }

Hence, electrical work can be expressed as multiplication of current, voltage and time

A = IU \Delta t

This, by the way, gives us that 1Joule = 1Volt·1Amper·1second

Since the Ohm's law gives us this equation

I = \frac{U}{R}

We can also express electrical work like this:

A = I^2R \Delta t \\ A = \frac{U^2}{R} \Delta t

Since power is the rate of doing work per unit of time, we can express electric power as

P = \frac{A}{\Delta t}

And, finally,
P = IU \\ P = I^{2}R \\ P = \frac{U^2}{R}

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