A multimeter is a pretty popular device in certain circles. Still, it seems that it’s not as popular as it deserves to be in the DIY and home-improvement communities. Those who are familiar with the electricity sector know-how vital multimeters are in various applications and uses. In simple terms, a multimeter is a device that can provide a myriad of functions that would otherwise require separate devices.The most common functions in any multimeter are ammeters, voltmeters, and ohmmeters. It can also measure the frequency of power lines, in addition to the capacitance and transistors. The process is quite simple since it only involves connecting the two protruding parts of the multimeter to exposed wires; the reading is shown on a digital or analog screen. If you’re still wondering about the usefulness of a multimeter, here are a few good reasons why you need to own one.Battery TestingAlmost every DIY enthusiast has this box or drawer full of old batteries, and they have no clue how they got there. This accumulation of batteries over the years doesn’t necessarily have to be a bad thing when you own a multimeter. Rather than testing out every single battery in your appliances or devices, you can use a multimeter to know which ones are working correctly. The multimeter has a voltmeter that is used for measuring voltage, and standard AA and AAA batteries should show 1.5 volts on the screen. If you see a match between the two values, it means that the battery is working correctly.Diagnosing Extension CordsHaving an extension cord that’s been left for a while can probably mean a lot of disappointment when you try and reuse it again. To know whether the extension cord is up to the task, you should use a multimeter’s continuity test mode. Insert the black probe of your multimeter in the cord receptacle and ensure the red probe is in contact with the end of the cord. The digital multimeter will emit an audible tone that should tell you whether the connection is good enough. Not hearing a sound can mean that this cord has the potential to short-circuit, saving you a lot of expenses and damages beforehand.Testing of BulbsWhile simple incandescent bulbs are a dime-a-dozen, you probably have a lot lying around that you’re unsure of their performance. Before you get yourself hurt by testing every single one out, a multimeter can facilitate this whole process and tell you which ones are good enough to be used. You’ll use the continuity test mode that’s also commonly used with extension cords diagnostics. The black probe should be in contact with the bulb’s metal end, while the red probe should touch the metallic circle at the end of the bulb. If you hear an audible sound, it means that this bulb can still provide you with light safely.Diagnosing a Hot WireInstead of replacing half the electrical wires in your home, you can pinpoint the exact hot wire that’s causing you issues with light switches and many other devices through the usage of a multimeter. First, you’ll want to turn off the power from the breaker panel and then take a look inside. Safely disconnect the wire connected to the switch in question. Turn on the power again and use the multimeter to test whether the electrical power being fed to the house is reaching the switch at all or not. If the switch is working fine, then all you need to do is replace the wire and vice-versa.Testing Electrical Sockets or OutletsThis test is a rather risky one if you don’t know what you’re doing because there is the possibility of getting shocked if you don’t exercise extreme caution. The wall outlets of your home may seem to be working while delivering the wrong voltage to your devices.The standard voltage that should be coming out of most outlets is 110-120 volt. If the reading on the meter’s screen between the hot and neutral slots is within 110 to 120-volt, switch to testing the hot and ground slots. If the reading doesn’t change, it means that your outlet is working fine. But if it does, you’ll want to make sure to call an electrician because the wiring is improperly done, which is a dangerous fix to do on your own.A multimeter may seem like an obscure device that you won’t need in your projects. But you want to persevere through that first impression to get to know the true potential multimeters offer in any DIYer’s life. Whether you’re looking for elaborate electrical projects or simple ones in your home, a multimeter is an indispensable tool that will help you in your endeavors.