# What is the difference between a kVA & a kW?

You may want to find out the difference between kVA - kW. Well in basic electronics, you learn that in a Direct Current circuit:

Power (**Watts**) = Voltage (**Volts**) x Current (**Amperes**)

Nevertheless, **1W = 1V x 1A = 1VA** is not always the case.

- It is
**true**in a direct current (DC current) circuit. - It is
**not true**in an alternating current (AC current) circuit.

The power required by the computer is **65W**. This charger will deliver **65W** in **DC current** (Direct Current) to the computer. This is described in the red circle, and also in the bottom rectangle, which describes the **output** (the electricity going out of the charger and into the computer). The **input** (electricity coming from the plug) is a little bit more complicated, because it is in AC current (Alternating Current). This one is shown as being:

**100-240V ~ 1.5A**. In the US, plugs supply current at around 110V. Therefore the requirement for this power cable will be :

**110V x 1.5A = 165 kVA**.

One must apply a Power Factor to this AC result in order to obtain the average power in kilowatts. A power factor is a measure of the synchonisation of the phases of the Current (in Amperes) and the Voltage (in Volts). A perfect synchronisation give the Power Factor a value of 100%, and the lowest synchronation possible gives the Power Factor a value of 0%. In real life, the power factor is usually in between 30% and 90%.

165 kVA x 40% = **66 W.**

This is an approximation, for a Power Factor of 40% is rather low for a computer charger, but it is a way for you to calculate your appliance's power in Watts from information in Amperes and Volts.