Wednesday, June 4, 2014
Defining Amps Without Ohm's Law
Here is a pretty basic question : What are amperes (amps for short)? Many folks will tell you using Ohm’s Law. However, defining volts, ohms, and amps in terms of each other is circular logic – it does not really explain what they are – only their relationship to each other. Amperes have a definition that does not involve Ohm’s Law. Amps are a measure of electrical current flow. The flow part is important. This means that time is involved. Amps are not really a quantity, but a rate. One amp is the flow of one coulomb of electrical charge per second. Note that the coulomb is the quantity and the ampere is the rate. Compared to gallons and gallons per minute (GPM), Coulombs are like gallons and amps are like gallons per minute (GPM). A gallon is a quantity – a specific amount of water. A gallon per minute (GPM) is that quantity of water moving in a minute. To have GPM, the water has to be moving and there is a time involved. Amps are the same way: the electric current must be moving and there is time involved. So what about Ohm’s Law? Well it is great for explaining the relationship of volts, amps, and ohms. I just find it useful to explain the concept of amps as a measure of current flow first.