Ammeters – The Science Squad Explains All

The ability to measure electricity or current on a circuit is critical for many applications. From laboratory experiments at school to problem solving electrical issues, ammeters are used very often in all kinds of situations. In this guide, the Science Squad are answering what an ammeter is, the different types available, the difference between an ammeter and a voltmeter, and how to use this device to measure a current. Read on for everything you need to know about ammeters. 

What Is an Ammeter?

Ammeters get their name from ampere meters, and amperes are commonly known as amps. This is a unit for an electric current, so put simply an ammeter is a device which measures the current of electricity in a circuit. These devices work by measuring the continuity and the draw of a particular circuit. The draw is the flow of electricity, whereas the continuity is the steadiness of the current and any interruptions to it.

Technicians often use ammeters to detect issues within an electric circuit. They can reveal if there is an unusually low or high current which could be caused by various problems. This kind of equipment is essential for diagnosing faulty electrical items, and ammeters are commonly used for everyday tasks such as changing a fuse. 

What Are the Different Types of Ammeters?

As with all types of laboratory equipment, ammeters come in various designs. The most widely used types of ammeters are:

• Analogue Ammeter: An analogue ammeter shows the reading of current using a dial and a pointer. These could come as moving iron ammeters, moving coil ammeters, or moving magnet ammeters. Most applications tend to use a moving iron ammeter because they can be used to measure both direct currents (DC) and alternating currents (AC).
• Digital Ammeter: As the name suggests, digital ammeters use a digital display to show the reading. This makes them very effective for use in poorly lit areas, making them a popular piece of kit for factories and other industrial environments. Depending on the model, a digital ammeter can be programmed to display alerts for various circumstances, for example if the current reaches a specific level.
• Clamp Ammeter: Clamp ammeters are a sort of hybrid device which combines measuring currents with insulated clamps which can be closed over conductors or wires. Also known as amp clamps, this kind of equipment is commonly used by electricians.
• Microammeter And Milliammeter: If you ever need to measure very low currents of electricity, you might need a microammeter or milliammeter. These devices measure in microamperes, which is one-millionth of an ampere, or milliamperes, which is one-thousandth of an ampere.

What Is the Difference Between an Ammeter And A Voltmeter?

Ammeters are quite commonly confused with voltmeters, because they are both used to measure electricity. However, these devices are very different, and it is essential that you understand why. Voltmeters are instruments which are used to measure the voltage across two points on a circuit. This varies from an ammeter which measures the flow of current. Voltage and current are the two ways that electricity can be measured, but you need a different device for each. The way these instruments are used within a circuit also differs, as a voltmeter will be connected parallel to the circuit, while an ammeter is connected in series.

How To Use an Ammeter to Measure Current?

Using an ammeter is often considered more challenging than a voltmeter, because the device needs to be part of the circuit in question. Ideally, when this kind of instrument is added to a circuit, it won’t drop any voltage as the current will run through it. If an ammeter is used in parallel to the circuit, like a voltmeter, it can cause a surge in current and damage the meter.

Exactly how to connect the device to a circuit will depend on the type of ammeter you have. Some use the same jacks for measuring current, voltage and resistance, whereas others sometimes have a separate jack just for the test lead plug for current measurements. With most basic ammeters, you can use a crocodile clip to attach the black lead near to the negative terminal, and the red lead to the positive terminal.

Once connected, you should be able to take your reading using either the digital display or needle, depending on your device. When using an ammeter, safety is key, so make sure to always wear insulated gloves to protect yourself from the live current.

So, there you have it. Our Science Squad have done it again. Great job guys!