(alternating current)
ELECTRICAL CURRENT
As we explained in our last post, voltage in an electrical system is analogous to pressure in a water system. In a similar manner, current in an electrical system is flow in a water system. We used the analogy of a water hose and demonstrated how you can test for pressure by placing your finger over the end of a dripping hose. If you leave your finger off of the end, and the water drips out, that dripping is the flow in the system. Similarly, electrical “current” flows.
As an aside, current flow is made up of electrons, moving past a particular point. Just as we classify water flow in gallons per minute, we classify current flow in terms of the amount of electrons which flow past a point. Specifically, one coulomb of electrons in one second is equal to one ampere, where a coulomb is a really big bunch of electrons, probably more than we want to count. This leads to a problem of how to measure amps since we really don’t want to count all those tiny electrons. In order to measure amps we will need some kind of amp meter. There are many types, but primarily two main types. First is a multimeter which has the capability of measuring amps, and the second most common type is a “clamp on” type, with spring loaded jaws which clamp around a wire which is carrying the current we need to measure.
Both of these common amp meters are readily available at hardware stores such as Home Depot, or Sears. A multimeter can measure amps, but to do so you must break the circuit by cutting the wire and inserting the meter into the circuit. The main advantage of the clamp type meter is that you don’t need to break the circuit. You simply clamp the meter around the wire and set the meter scale to read the current flowing in the circuit.
Summary: current in an electrical system is the flow of electricity through a wire. We can measure the amount of current flow with several different kinds of meters.
(direct current)
Our next “lesson” will be about electrical “POWER”.