We hear the term watts quite often in our day-to-day lives, whether it comes to electricity or electronics. But how can I convert volts to watts? The short answer is that you can’t! This is because the wattage of an electronic device doesn’t depend on its voltage. Instead, wattage depends on two other parameters: current (or amperage) and resistance.
1. What is a Volt?
A volt is a measurement that describes the magnitude of an electric potential. You can think of a volt as the energy per unit charge, measured in joules per coulomb (J/C). The symbol for volt is V. When you see a volt, you’re seeing how much energy is required to move a certain charge through a specific electrical resistance. For instance, if I say I have determined that I need 3 volts to play “Jingle Bells” on my electric guitar, this means that 3 v· = 3 x 0.3 = 3.3 J. Here in IEEE Standard Century Dictionary, we have two sifted definitions for “jingle bells” listening:
(1) Means playing “jingle bells” by ringing two bells simultaneously.
(2) Means playing “jingle bells” by playing two distinct musical notes at the same time.
If a guitar requires 3 volts to play an electric song, then the musician is capable of generating:
Therefore, the only thing that defines the output of a guitar is its voltage, not it’s current. A 1 amp circuit that requires 10 volts to run — in other words, 5 V — would therefore be:
Adding together the definitions for winning and running a circuit of a given magnitude will result in:
5 V x 10 A = 15 V
Considering that amps are often used to describe the power of electric circuits, this would mean that “5 V is the equivalent of 15 A.” These are certain words that mean the same thing and are easy to confuse. The symbol for power is P.
However, this is also a confusing symbol because P stands for power, but in a different unit of measurement, namely watt-hour. Watt-hour is a unit of power output for a PC computer. Likewise, 1 watt is equivalent to 5.6 J or 15.6 watts, which makes the equation between the two terms:
15 W· = 15 V x (1.
2. How to Convert Volts to Watts
The most common question we get here at Cynerd is “How do I convert volts to watts?” You’re in luck because I’m going to give you a super quick and easy way to do it.
First of all, we need to get the units right. In most countries, the SI unit of voltage is the volt (V) or British thermal unit (V BTU). In the USA, the unit is volts (VD), and it’s closely related to the watt (W). All other countries keep their units of measurement the same.
Unfortunately, calculating watts (the ‘base’ unit of electricity in the United States) is more or less cumbersome. Here in the United States, there are only 5 watts available per horsepower- the power produced by a motor at the wheels. However, the SI unit for power, which we mostly use in other countries, is kilowatt (or amp). Again, the common name for this is horsepower.
Unfortunately, for our purposes in the United States, the methods used to convert volts (British thermal unit) and watts (SI unit) don’t translate very well. Also, this text from the Wikipedia article on power:
“Watts are the unit of energy in the metric system. They are usually used to describe electrical output, such as light bulbs, dryers, machinery, and gas energy in a home’s electricity bill. Probably not related to the number of watts powering an appliance.”
The most common way to calculate size is in ‘peak’ values. This is the value that results when dividing the input voltage with the output voltage multiplied by the product of their respective power outputs. Using a 3.0 S3 Cell with a power output of 50W from a 10kVA power supply, for instance, we would divide the input voltage (3.0 V) by (1.1 X 50W) = 71.2. Scary? Yep.
Then we multiply by 100 to get watts.
Example: 1.1 X 50W = 71.