# Electric meter

Figure 1. A North American electric meter.[1]

An electric meter is a device used to measure the electrical energy usage of a home, building, or other electrically powered device. They are used in order to provide accurate billing to customers.[2]

Electric meters make use of various coils and gears, however its operation can be simplified to that of an electric motor. The electric current moving through the coils produces changing magnetic fields in which a metal disc responds to. With the help of a permanent magnet, the disc spins proportional to how much electricity is used. Its motion rotates gears which finally show the reading on a clock-like dial.

## Contents

An electric meter seems complicated with all of those spinning dials each rotating in opposite directions, however it isn't too difficult once the secret is revealed. The following video provides an excellent guideline on how to read an electric meter, which is summarized below.

### Steps

1. Start at the far right dial. Record the digit that the dial is on, or if it is between two digits record the smaller of the two.
2. Now read the dial to its left, again recording the smaller of the two if it is between two digits.
3. Continue until the far left dial is recorded, then read the recorded number normally.

### Notes

• If the dial is between 0 and 1, 0 is the smaller number. However, if it is between 9 and 0, 9 is the smaller number (just like on a clock, where 12 is less than 1).
• Remember that these dials are all interconnected. If it's unclear whether the dial has passed a number or not, read the dial to its right - if it has passed 0, the next dial is past the number.

The number given by the meter is measuring the electrical energy used (in kilowatt-hours, unless otherwise stated on the meter).

Example: if the numbers from the meter in the following order from right to left - 1, 3, 4, 2 - then 2431 kWh have been used. Take a look at the meter in Figure 1 (click to expand) and try to read it (it reads 2211 kWh).