Multimeter facts for kids
A multimeter is a super handy electronic tool. Think of it as a Swiss Army knife for electricity! It combines several measuring devices into one unit. It usually includes an ammeter, a voltmeter, and an ohmmeter. If it's a digital one, people often call it a DMM.
Modern multimeters can measure more than just basic electricity. They can also check things like frequency (how fast electricity wiggles), capacitance (how much charge something can store), and even temperature. Because it can do so many tests, it's often called a "multitester." Sometimes you might hear it called a VOM, which stands for Volt-Ohm-Milliampere.
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What Can a Multimeter Measure?
A multimeter is great for checking different parts of an electrical circuit. It helps you understand how electricity is flowing.
Measuring Voltage
Voltage is like the "push" or "pressure" of electricity. You can use a multimeter to measure the voltage of a battery, like a AA battery or a car battery. You can also measure the voltage between two points in an electrical circuit. To do this, you connect the multimeter's probes across the two points you want to check. This is called connecting it "in parallel."
Measuring Current
Current is how much electricity is actually flowing, like how much water flows through a pipe. To measure current, you usually need to connect the multimeter in a special way, so the electricity flows through the meter. This is called connecting it "in series." It helps you see if enough power is getting to a device.
Measuring Resistance
Resistance is how much something tries to stop electricity from flowing. Think of it like a narrow part in a water pipe. A multimeter can measure resistance in ohms. This is useful for checking if a wire is broken or if a component is working correctly. If a wire has very high resistance, it might be broken inside.
Types of Multimeters
There are two main types of multimeters: analog and digital.
Analog Multimeters
An analog multimeter uses a needle that moves across a scale to show the measurement. It's like an old-fashioned clock with hands. These meters are good for seeing changes in a measurement over time. They don't need batteries to measure some things, like resistance.
Digital Multimeters
A digital multimeter shows the measurement as numbers on a screen, just like a calculator. These are very popular because they are easy to read and often more accurate. Many digital multimeters also have extra features, like holding a measurement on the screen or beeping if there's a connection.
How to Use a Multimeter Safely
Using a multimeter is generally safe, but it's important to be careful, especially when working with higher voltages. Always read the instructions that come with your multimeter. Make sure you select the correct setting (voltage, current, or resistance) before you connect the probes. If you're not sure, it's always best to ask an adult or someone experienced for help.
Images for kids
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An analog multimeter, the Sanwa YX360TRF
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1920s pocket multimeter
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Avometer Model 8
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A pocket-watch-style meter made in the 1930s. It can measure voltage, current, continuity and the heating element of vacuum tubes.
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A 4+1⁄2-digit digital multimeter, the Fluke 87V
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A clamp meter
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Display face of an analog multimeter
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A bench-top multimeter, the Hewlett-Packard 34401a.
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USB-powered multimeter for examining battery charging of portable electronics.
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Inexpensive analog multimeter with a galvanometer needle display
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Multimeter test leads
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An example of input protection on the CAT-IV rated Fluke 28 Series II Multimeter
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See also
In Spanish: Multímetro para niños
