In engineering, what is power and how can you use it? What is electricity? What is magnetism? These and many other questions are answered in this introductory course on what is power. The topic briefly covers the definition of electricity, what is the magnetic field, and how electrical motors work.
In physics, electrical power is simply the amount of electrical energy transferred or produced per unit of time. In the International System of Units, which is commonly referred to as the IEE, the single unit of electrical power is the watt, equivalent to oneiwe/sec. In earlier works, electrical power is often referred to as direct current.
Electrical power can be measured in joules per second or kilowatts. One might prefer to write it in joules per minute or kilowatts, but it does not really matter. Some people prefer to write it in a unit of watts. This way, they can better understand the meaning behind the term. It means how much power is used in completing one circuit.
One might conclude that what is power when we talk about electrical power would be very easy to understand, but what is power when it comes to a circuit is a bit more complicated. The term circuit simply refers to a group of wires connected to each other. This kind of wiring is used in various different ways, such as in an automobile to make a car move. A power cord is a common example of a circuit.
How long does a circuit last? If you connect three wires of the same size and same gauge of wire to a circuit, what is power? About thirty seconds. If you try to connect three wires of the same size, of different gauge and the same gauge of wire to a circuit with a much bigger cable, what is power? About forty-five seconds. So, when we speak of how much power is present in any electrical device, we are talking about only a small amount of power.
The amount of power that is present in any electrical device depends upon how long it has been transmitting through a circuit. In other words, if you use a cell phone for one minute, it will have maximum transmission power for a short period of time. This may be power for sending and receiving an audio signal or it may be just enough to hold a conversation. What is power, then, if you can send a signal for a short time and then it becomes quiet?
The question, then, becomes how is it determined that what is power? It is determined by the work that has been done, either by an electrical machine or by some other source. If the work is done at high temperature or if it is done under very low temperatures, then the results will be very different from those that are done under ordinary conditions. The work done at very high temperatures or under very low temperatures gives a lot of electric energy, so that if you place your hand on the device, it will feel hot; and so, the weight will become much heavier than usual.
One horsepower is defined as the maximum amount of electrical power that can be moved with a single movement of an object. It is measured in watts, or watts per minute. One horsepower could be used as a clock that counts down from one thousand to one hundred thousand seconds. One horsepower is equivalent to 20000 W. Therefore, a car that has a one-horsepower engine can move a mile per hour, which is about the speed of an electric train. How is it determined that what is power, anyway?