## DC Ohm’s law calculator

Enter **2 values** to get the other values and press the

*Calculate*

button:

#### DC calculation

Voltage (V) calculation from current (I) and resistance (R):

*V*_{(V)} = *I*_{(A)} × *R*_{(Ω)}

Complex power (S) calculation from voltage (V) and current (I):

*P*_{(W)} = *V*_{(V)} × *I*_{(A)} = *V*^{
2}_{(V)} / *R*_{(Ω)} = *I*

^{2}_{(A)} × *R*_{(Ω)}

## AC Ohm’s law calculator

Enter **2 values** to get the other values and press the

*Calculate*

button:

#### AC calculation

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*|) ∠ (*θ _{I}* +

*θ*)

_{Z}The complex power S in volt-amps (VA) is equal to the voltage V in volts (V) times the current I in amps (A):

*S*_{(VA)} = *V*_{(V)} × *I*_{(A)} =

*(|**V**|*×*|**I*|) ∠ (*θ _{V}* –

*θ*)

_{I}## Power factor calculator

Calaulate power factor, apparent power, reactive power and correction capacitor’s capacitance.

- Select phase number.
- Enter real power in kilowatts (kW).
- Enter phase current in amps (A).
- For three phase, select voltage type.
- Enter voltage in volts (V).
- Enter AC frequency in Hertz (Hz) – needed only for capacitance calculation.
- Press the calculate button to get the power factor.

The power factor correction capacitor should be connected in

parallel to each phase load.

## Single phase circuit calculation

Power factor calculation:

*PF* = |cos *φ|* = 1000 ×

*P*_{(kW)} / (*V*_{(V)} ×

*I*_{(A)})

Apparent power calculation:

*|S*_{(kVA)}| = *V*_{(V)} × *I*_{(A)} / 1000

Reactive power calculation:

*Q*_{(kVAR)} = √(*|S*_{(kVA)}|^{2} – * P*

_{(kW)}

^{2})

Power factor correction capacitor’s capacitance calculation:

*C*_{(F)} = 1000 × *Q*_{(kVAR)}

/ (2π*f*_{(Hz)}×*V*_{(V)}^{2})

## Three phase circuit calculation

For three phase with balanced loads:

#### Calculation with line to line voltage

Power factor calculation:

*PF* = |cos* φ|* = 1000 ×

*P*_{(kW)} / (* √*3 ×

V

V

_{L-L(V)}×

*I*

_{(A)})

Apparent power calculation:

*|S*_{(kVA)}| = * √*3

×

*V*

_{L-L(V)}×

*I*

_{(A)}/ 1000

Reactive power calculation:

*Q*_{(kVAR)} = √(*|S*_{(kVA)}|^{2} – * P*

_{(kW)}

^{2})

Power factor correction capacitor’s capacitance calculation:

*C*_{(F)} = 1000 × *Q*_{(kVAR)}

/ (2π*f*_{(Hz)}×*V*_{L-L(V)}^{2})

#### Calculation with line to neutral voltage

Power factor calculation:

*PF* = |cos* φ|* = 1000 ×

*P*_{(kW)} / (3 × *V*_{L-N(V)} × *I*_{(A)})

Apparent power calculation:

*|S*_{(kVA)}| = 3 × *V*_{L-N(V)} × *I*_{(A)} / 1000

Reactive power calculation:

*Q*_{(kVAR)} = √(*|S*_{(kVA)}|^{2} – * P*

_{(kW)}

^{2})

Power factor correction capacitor’s capacitance calculation:

*C*_{(F)} = 1000 × *Q*_{(kVAR)}

/ (3×2π*f*_{(Hz)}×*V*_{L-N(V)}^{2})

Source: RapidTables, Online Reference & Tools