Measuring Power and Milliamps
Milliamps are a measure of amperage, with 1,000 milliamps equaling one ampere, or amp. Both milliamps and amps are a unit of electrical current. An amp is the current required to produce a force between two parallel, infinitely long wires separated by one meter's distance.
Understanding Power Cord Strength
A 200 milliamp power cord does not put out as strong of a charge as a 300 milliamp power cord. This means that the current required to produce a certain force in a 200 milliamp power cord is less than that of a 300 milliamp power cord. However, a power cord with a higher milliamp number does not necessarily mean that it is a better cord. It only means that a 300 milliamp power cord will provide 100 milliamp in additional charge when compared to a 200 milliamp power cord.
Meeting a Device's Power Needs
A power cord's charge should meet the requirements of that which it charges. For example, an alarm clock might require 100 milliamps to function, so it would need a 100 milliamps, or 100 mA, power cord or adapter. A cell phone might require 1,000 milliamps, so it would need cord capable of producing 1,000 milliamps, or 1,000 mA. Check a user manual or consult with the device's retailer to verify what kind of power cord the device will need and whether the device can run on a power cord with a different milliamp potential than the device needs.
Matching Cord and Device Power
In some instances, using a power cord that provides more milliamps than a device requires is safe, as many devices will only use as many milliamps as the device needs to run. In other words, the device won't use the extra available milliamps. However, some power cords will fry and ruin devices if you use a cord that doesn't offer enough, or offers too much, milliamp potential. Check a user manual or consult with the device's retailer to verify that you can use a different power cord, if need be.