Explaining the Difference Between Voltage & Amperage

Electricity is a powerful force, but how powerful? How strong is an electrical current flowing through your walls? How dangerous is that electrical charge? These are all common questions that can be answered if you know how to measure and quantify different characteristics of an electrical charge. Electricity is measured in several ways, and there are a bunch of different names that you may have heard pertaining to different electrical components. Do you know what they mean and how they relate to one another? This blog has the answer—we’ll take a look at two of the most common electrical measurements: voltage and amperage.

Visualizing Electrical Flow

In order to better understand electricity, it helps to visualize it in your mind as something you can tangibly picture, such as a river flowing across the land. Water flowing through a river is actually a great way of visualizing electrical flow, as it helps us to better picture how electricity behaves in certain situations.

What Is Voltage?

Voltage is essentially a way of describing the “amount” of energy that is flowing through a line at any given time. We can represent that as the amount of water flowing through a river. A small stream or brook may have only a small amount of moving water, maybe a gallon or two every minute. A large river may see thousands of gallons of water pass every second. In this case, the smaller creek is representative of lower voltage and the major river is an example of higher voltage.

This is also a good demonstration of how high voltage can be dangerous, even at low current. There is a common myth out there that says “It isn’t the voltage that kills you… it’s the current.” The truth is that you don’t need a lot of current to make high voltage dangerous. Even an incredibly slow-moving river can sweep someone away in an instant.

What Is Amperage?

Amperage can best be described as the rate at which the energy is flowing over a line, and is measured in units known as “amperes,” or “amps” for short. Think of this sort of like the speed a river is flowing. Our slow-moving creek that’s only moving a few gallons of water per minute is far from dangerous. However, if that small creek were moving at a high rate of speed, even its small size might make it a hazardous landmark. The same thing can be said with our larger river. A slower-moving speed might make the river traversable by swimming or by boat, but faster movement is incredibly dangerous and can wipe out virtually anything in its path.

Every electrical connection can be described by these two quantities. Under normal circumstances, the one that you’ll probably encounter is voltage, as this is generally the most important one for a device’s functionality. For example, when a device says it is designed for a 120-volt connection, then any 120-volt connection will work. From there, the device will pull the current it needs in order to operate, be it one ampere, half of an ampere, or even multiple amperes for high-power devices. Every device currently plugged in and turned on while connected to an electrical circuit will draw at least a small amount of current, and more current places greater demand on an electrical circuit. Circuits are in turn regulated by circuit breakers that will trip and shut off if the drawn current exceeds what they are rated for.

Amperage is also important, however, as it can demonstrate the amount of strain currently on an electrical circuit. Think of it this way: have you ever tried to breathe through a drinking straw? You may be breathing at a fairly constant rate, but the small diameter of the straw prevents the air from coming in or going out as fast as you would normally expect it to. Eventually, if you put too much pressure into a straw, the straw itself could fail and burst. In this case, straws are a lot like electrical circuits: if you try to force the same amount of energy through components that don’t have the capacity to handle it, then the components could fail.

Wattage Explained

This quality can be exemplified through one final measurement that you likely have already heard of: wattage. Wattage is defined as the product of volts times the number of amps, and is the most common way of measuring the brightness of a lightbulb that you’d install in your home. The higher the wattage, the brighter the bulb. But this is so much more than just a brightness measurement—it’s actually a way of telling you exactly how much energy that bulb uses when it runs.

Say you have a 100-watt bulb installed in a lamp in your home. When you turn that blub on, it starts drawing its 120 watts of power (there is a time element to this measurement too, but we’ll skip that for now to keep things simple). If we do a small amount of math, we can come to the conclusion that that 100-watt bulb is drawing just a little bit over 0.8 amps of current from your electrical system. Under most circumstances, that’s totally fine. Most electrical circuits are designed to provide 15 or 20 amps of current at 120 volts. However, if that same circuit is already drawing over 14 amps due to everything else plugged into it at the time, flipping on that light could cause the breaker to switch, shutting down your entire system in order to prevent that “straw” from bursting.