How to Use an Ammeter

What You'll Need
Leads with alligator clips
Electrical circuit

An ammeter is a device that is used to measure the amount of electric current that runs through a circuit. The standard unit used to measure electric current is called an ampere (amp), hence the name ammeter or ampere meter. An ampere measures how fast electric charges pass through a circuit point. As current passes through an electrical circuit, an electromagnetic field is generated. This created field allows the needle on the ammeter to measure the electrical current on the circuit. In case of a digital model, the electrical field allows the screen to display the correct reading. Below is a simple guide on how to use an ammeter.

Step 1 - Determine what Type of Ammeter to Use

There are 2 different types of ammeters: analog and digital. An analog ammeter makes use of a needle similar to that found in a compass needle. The needle points to the particular amount of current that passes through the ammeter. A digital ammeter displays the measured current on a liquid crystal display.

Step 2 - Safety Preparations

Working with an ammeter means working with electrical current. Exercise caution when dealing with any electrical equipment that involves live wires or wires connected to an energy source. In this set up, it is best to wear gloves, check that the electrical circuit, the battery, and other materials are all intact.

Step 3 - Break the Circuit

A simple example of a circuit can be demonstrated using a battery connected to a lamp. The battery has both positive and negative terminals. Each terminal is connected in a series to the lamp. Break the circuit in a location where you want to measure the amperage. Disconnect a part of the circuit to make way for the ammeter. The device should always be connected to the circuit in a series.

Step 4 - Connect the Leads

There are 2 leads with different colors: red and black. Connect the leads to the device. The red lead should be connected to the positive terminal and the black lead should be connected to the negative terminal on the device. Using the alligator clip, connect the red lead to the wire nearest the positive terminal of the battery or power source. Do the same with the black lead, but connect it to the wire closest the negative terminal of the power source. Connecting the wrong lead to the wrong terminal will cause the device to malfunction.

Step 5 - Determine the Ammeter Reading

Reading the current measured by the device will vary depending on the type of device used. For analog ammeters, read the smallest division on the scale and round off the next digit. The needle will point to the approximate amount of amperage. For digital ammeters, there is no need to round off or read the smallest division on the scale because the reading is automatically displayed on the LCD screen on the device.

Even for simple repair or project, an ammeter can come in handy. You can use an ammeter for simple socket or electrical outlet repair or when changing busted fuse.