Everything You Need to Know about a Multimeter
If you’re trying to determine if a fuse is blown, a multimeter can do that. If you want to determine if a battery (car battery, 9V, AA, etc) has any charge left in it, a multimeter can do that too. In your home wiring you can determine if an outlet or wire has an electrical charge by connecting a multimeter to it. These all help you to save time and money by testing things at home by yourself.
Let’s review many of the important things you need to know about a multimeter.
What kind of multimeter should you buy?
When you decide what kind of multimeter to buy you should use the same logic you would with anything else like a car, house or computer. Go with those that meet your needs.
If you need a multimeter for professional use and need something high quality then go for the best Fluke type multimeters as that brand is top of the line. The Fluke 87-V digital multimeter is a great choice for this.
If you’re just starting out and want to play around with it before you spend a lot of money then just buy one of the digital multimeters around $20 USD. The Innova 3320 digital multimeter is a great choice as a starter device for you.
What not to buy?
If you see the old-school multimeters with the needle that moves across a scale, that is not a good multimeter. To say the least, it would be a huge waste of money considering you can get a digital multimeter that is extremely more accurate for the same price if not cheaper. Get the one with a digital screen that displays numeric values which is called a digital multimeter.
What measurements are important to you?
There are different types of multimeters and different measurements it can do so it’s important to understand the basics of it’s measurement capabilities. Lets understand each of these below:
Ranging
When selecting a multimeter, you have to decide whether you want a manual or auto ranging device. Since there are many different measurements you can make knowing what the range of those measurements are is tricky.
If you’re a new user then I’d suggest you pick a multimeter with an auto-ranging capability. For auto-ranging multimeters it will assess the electrical current and then determine what range to use automatically. This often takes some time to complete so for those experienced users they often prefer a manual ranging so they can control it.
Pick one based on your preference, although, in my experience most people choose one based on their patience if they don’t want to wait
Each multimeter should say if it’s manual or auto ranging but if it doesn’t you can always look at the dial on the device. If you see numbers around it then it’s a manual ranging. If you only see symbols/letters then it’s auto-ranging.
Values
While you may not know what the different symbols and letters mean right away you should be somewhat familiar with the important terms:
- DC/AC: Direct Current and Alternating current. You can change this by simply pushing a button or selector on your multimeter. The difference in these two currents is simple in that with DC the flow of electricity is only going one way where as in AC the current can flow in one direction and then change to the other direction.
Most electrical outlets are AC which is easy as they usually have a large grid to work on and can transfer power back and forth to eliminate waste. Most electronic devices and household appliances work on DC as they only require the power source to go one way to the device. - Continuity: This allows you to test if there are breaks in an electrical circuit like a faulty/cut wire etc. It sends electricity into one end and checks if it has a response on the other end.
- Voltage: This measures how strong electricity is being pushed through a specific circuit. The higher the voltage the stronger the force. This is measured in Volts (V).
- Current: This measures the amount of electricity going through a circuit and is measured in amperes (A).
- Resistance: This measures the difficulty of a current of electricity to flow through an object. The higher the resistance means it’s more difficult for energy to flow through it. This is measured in ohms (Ω).
There are many other values including frequency, capacitance, transistor, temperature, etc, but those are useful to specific situations and may not be needed if you are an average at-home user. If you want something that can test everything, then for a little bit more money you can invest in a good quality one that has more options.
How to set up your Multimeter
First thing to do is to give it power. Most multimeters use a 9V battery although some still use AA batteries. Check which one yours needs and if it comes with one or not before you head home with it.
Black and red leads will also come with your multimeter and most of these will need to be plugged into it in order to use it. Simply plug the black lead into the one that says COM and the red one into the one for Volts (labeled with V). You may need to change the red one for different measurements but the black one always remains constant.
Plugging these in wont hurt you to start but it’s best to only ever touch the colored rubber part of the leads and never touch the metal parts if you want to avoid getting shocked (which can be dangerous).
From here you can start to learn the different ways of measuring objects, devices, outlets, fuses and different car parts.
