What Is An Ampere?

Have you ever heard the word “Amp” and wondered what it meant?  Amp is the shortened version of Ampere, a SI unit to measure electric current, named after André-Marie Ampère.  André was a French physicist, mathematician, and one of the founding principals of electromagnetism. André brought electrodynamics and science education to light during the French Enlightenment, in the 18th century.  This included discovering Ampere’s Force Law, which is a theory in electrodynamics that explains attraction or resistance between two wires or circuits that contain electric current.

An electric current is a flow or stream of electrical charge within a circuit.  To describe an electrical current, you may think of it as the reaction that occurs as well as the number of electrons that flow, when electricity travels through a wire to bring power from point A to point B.  Electric currents typically travel through the wiring of some sort, to use common products like charging mechanisms, appliances, or essentially any type of product that has a cord and needs to be plugged in to be used. 

You may have noticed that certain household electric-using products have a specific wattage application necessary to actually work, such as a light bulb.  To break this down further, amps refer to the amount of electricity used by a product, while volts are the actual measurements of the force of that electricity.  Multiplying the two would give you the workload, or total wattage of the product.  A watt is calculated by multiplying amps by volts. 

Watts = Amps * Volts 

120 Watts = 1 Amp * 120 Volts

By checking your home circuit breaker box, you can determine what amperage rating your household circuit has.  Most homes in the United States are wired with a circuit of 120-volts and most use 15-amp receptacles or 20-amp circuits for larger household appliances such as dishwashers, refrigerators, freezers, washers, and dryers. 

Battery banks can be helpful in times of electric outages, as they offer electricity if primary sources aren’t available.  They are rated for a specific quantity of amp-hours.  Amp-hours (Ah or amp hr) are used to define how much amperage can be provided by a battery within one hour.  The rating is usually categorized and measured in milli-amp hours or mAh.  The amp hour rating can usually be found on deep cycle batteries and the measured quantity refers to the battery capacity.

There are a couple of ways to measure amperage or electricity within a circuit.  One method would be to use an ammeter.  Typically, an ammeter uses a voltmeter, has a small area of application within a circuit, and measures resistance within that circuit.  It’s not used to test transistors or diodes.  Alternatively, a multimeter is used to measure more in-depth information and parameters within an electrical circuit as well as multiple electrical properties.  They can be used to test transistors and diodes and can be used to substitute an ammeter.  Ammeters, however, cannot substitute multimeters as they are only used to read an amp measurement.

We hope this helps you understand more about amps and how they came to be as well as how and why they are used.