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A voltmeter, simply described, is an instrument that measures electrical voltage. More technically, a voltmeter measures the electrical potential difference between two points in an electric circuit. Voltmeters are often used to detect the capacity of batteries and whether they need recharging, but they can also be used to measure the voltage of other energy sources such as solar panels.
Voltage measurement is also important in terms of the efficiency of appliances, as many devices such as magnet motors work more efficiently when designed to operate at higher voltages.
Electricity is measured in three basic ways, volts, watts, and amperes. Each unit measures a different aspect of electrical current. A related unit, the ohm, measures resistance, which is an important factor in determining some of the other measures.
The ampere is a measure of the volume of current, the voltage is a measure of its rate of flow or intensity, and the watt uses a product of the two to generate a figure for available power.
A common analogy used to describe these various measures of electricity is water pressure. If you have a hose, two factors determine the force of the water emerging from the hose.
One is the amount of water being put through the hose. The other is the speed at which the water is emerging, which is a function of that volume of water and how restricted the hose is (a wider hose will result in lower water pressure from the same volume of water). You can get an idea how this works using a simple garden hose.
Turn the water on about halfway. You will see the water emerge from the hose, rise to a certain height and drop. Now turn the water on the rest of the way.
You will see the height at which the water emerges increase, showing that the water is coming out under increased pressure due to the increase in the water volume going through the hole. This is comparable to increasing the amperage of an electric circuit.
Now turn the water back down to halfway so that the flow from the hose is reduced again. Place your thumb over the opening of the hose so that the flow of water is restricted.
You'll see the water shoot up to a higher pressure, just as it did when you turned the water on higher. This is comparable to an increase in voltage: it's not an increase in the volume of power, but in the rate at which it is transferred, comparable to increasing the pressure.
The actual power generated by a source or used by an appliance is usually measured
in watts, which depends on both the voltage and the amperage of the current (a higher-
Measuring the voltage of a current is primarily important for reasons of energy efficiency.
Electricity at higher voltages results in improved efficiency. The automobile industry
is moving towards a 42-
Actually, voltmeters are not used as often as multimeters, which incorporate measures of resistance (ohms) and current (amperes) as well as volts. That said, measuring the voltage of a current is desirable to determine the efficiency of a battery source, which is usually measured in volt output. It is also a useful measure of current strength along a long cable or other transmission line, as voltage tends to drop over long distances.
Generally speaking, the higher the voltage, the greater the efficiency of an electric current. Higher voltage allows more work to be done by a given current strength (amperage). It's important, then, to be able to measure the voltage of a current and maintain it at a strength that is usefully high.
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