The Best Multimeter: Which One?
If you are looking for the best multimeter, then you have come to right place. You will get all the answers from our experts. They are experienced professionals with years of experience in different fields of technology and they provide their valuable opinions on various products.
So, what’s your question? Do you want to buy a new digital multimeter or do you need some old analog one? Are there any features which make a difference between them?
You may ask these questions because you don’t know the answer yourself. You might even think that you already have such a device, but it doesn’t work properly anymore. If so, then it would be very useful to read this article about the best multimeter. It will give you all the necessary information to choose a suitable one for your needs.
What Is A Multimeter Used For?
A multimeter measures electrical current. This means that it determines how much electricity is flowing through a circuit. You can use it to check if a light bulb works properly, to measure the voltage of your battery charger, or even to test whether your car engine is working correctly. All these tasks require measuring currents.
In addition, a multimeter can be used in many other ways besides measurement. For example, you can use it to find “hot spots” in a electric wire that might indicate a short circuit or other electrical problem. So, it is definitely an important and useful tool to have.
How Does A Multimeter Work?
The first multimeters used an analog system of measurement. This means that there was a needle which moved over a scaled circular graph. It was possible to read the level of current just by looking at the position of this needle on the scale.
Most multimeters today are digital. They work by converting the measurement into a number which is then displayed on a screen.
The advantage of an analog multimeter is that it works even if there is a power cut. A digital one requires batteries or another power source in order to work, so it can stop working if there is a power failure.
What Is The Difference Between AC And DC?
One of the most important differences between multimeters is whether they are designed to measure alternating current (AC) or direct current (DC). A digital multimeter can switch between AC and DC, but an analog one will only be able to measure one type.
Do you need to measure both or just one?
If you are not sure, then a multimeter which can do both can be very useful. It can be used for basic electrical work in the home as well as in a car repair shop.
What To Look For When Buying A Multimeter?
It would be very difficult to choose the best multimeter for you if there weren’t any standards. Luckily, there are standard sizes and types of multimeters, so it is much easier to compare different models.
There are four main types of multimeters:
The cheapest ones have only two leads and work with only a few measurements. This type is not very accurate and difficult to use, so it is not very popular.
The next type has two leads and a digital readout. It can measure larger currents, but it is still quite cheap and not very reliable. These models are the least expensive multimeters which provide any sort of accuracy.
The most popular and reliable multimeters are the ones with a digital screen and at least two sets of leads. These are affordable, easy to use and provide accurate results.
The last type is the advanced multimeter, which has four sets of leads and an analog display as well as a digital one. These are more expensive and mainly used in laboratories.
As a beginner, you don’t need to buy an advanced multimeter. Even the basic one will be more than adequate for most purposes.
Things To Look For When Choosing A Multimeter:
Pick a multimeter which has the features you need and fits your budget. If you only need to check lamps and wall sockets, then a simple model will do. However, if you want to work on cars or other electrical devices, then it makes sense to buy a more expensive multimeter which can handle the higher currents involved.
The main thing to look for is the technical specifications.
What range of measurements can it make and how accurate is it?
Look for features like voltage detection, continuity check and frequency measurement. The more features, the more expensive the multimeter, but you will be able to use it for a wider variety of jobs.
Remember that your multimeter is just a tool. A cheap one will work well enough for you to learn how to use one. Only buy the best model if you find that you are using it a lot.
Your multimeter is a precision measuring device and needs to be treated carefully. Don’t drop it or expose it to dust and dirt, because this can affect the measurements.
If your multimeter has a rechargeable battery, remember to charge it from time to time. Leaving it for too long can permanently damage the battery and it will not take a charge anymore.
Most importantly, NEVER test a live circuit with the probes. This can be very dangerous and you could get an electric shock. When you are working with electricity, always ensure that the power is off at the mains.
Don’t try to modify or hack your multimeter in any way. The internals are very delicate and any small mistake can destroy it completely. Manufacturers go to a lot of trouble to make them as safe as possible, so there is no need to try modifying one yourself.
How To Use A Multimeter?
Learning how to use a multimeter takes some patience and practice. However, once you have learned how to use one safely and effectively, you will find it a very useful tool.
When you first buy a multimeter, read through the manual first. The manual will tell you how to use it as well as how to take care of it. When using a multimeter for the first time, always check that it is functioning correctly. Set it to the lowest range, then touch the probes together.
The multimeter should register a very low voltage, which is displayed in Volts on the screen.
Now move the probes apart very slowly and watch the meter reading. As you separate them, you should notice that the meter reading increases slightly. This is known as the ‘centre tap’ setting and is used for measuring resistance in live wires.
To measure voltage in a circuit, set the multimeter to the highest range. Touch one probe to the positive battery terminal and the other probe to the negative terminal. The meter should now read a number close to the voltage of your battery. (Some multimeters automatically turn off after a few minutes.
If this happens, just press the ‘On/Off’ button again to get it working again).
To measure current, set the multimeter to the ‘A’ setting. Again, touch one probe to a battery terminal and the other to the device you want to test. The meter should now read a number close to 0.1 of the amperage being used.
Remember that current is measured by how many electrons are flowing past during a certain amount of time. As the electrons are very small, this measurement is most accurate when taken over a very short period of time.
Most meters have a ‘Continuity’ setting that you can use to check for live wires. Set the dial to this, then touch the probes together and move them around an area. If the meter beeps or displays a number other than ‘OL’ (meaning Open Load), then there is a wire connected to that point. You can use this setting to check wires without having to apply power.
When you have finished using a multimeter, remember to turn it off. Leaving it on will eventually drain the battery and could potentially damage the meter.
Remember to never test mains-voltage (numbers with two digits and a ‘P’ after them) with a multimeter set to anything above 20 volts. Mains voltage can kill instantly and cause severe burns. If you need to measure it, do so at the fusebox or at the plug. Also, remember to be extremely careful when dealing with anything that plugs into the wall.
Resistors are electronic components that resist the flow of electrons. In a circuit, they are used to limit current, which is important when wiring switches and lights because you don’t want to blow a fuse or circuit every time you flip a switch.
A common type of resistor is called a ‘Ohm’. They come in various sizes, with each number representing a different size. For example, a 36 Ohm resistor is much smaller and weaker than a 3.6 Ohm one.
The larger the number, the smaller and weaker the resistor.
Resistors can be wired in series or parallel to each other. When wired in series, the voltage is split between them all, while the total resistance remains the same. For example, ten 1 Ohm resistors wired in series will create a total resistance of 1 Ohm, however the current is also shared between all of them. This means that each resistor will experience 1/10th of the current, making it much less likely to overheat.
However, resistors also have a ‘power rating’ which measures how much power they can handle. When wired in series, the power rating is divided by the number of resistors. For example, two 50W resistors in series can handle 25W, three 32W resistors can handle 10.7W and four 20W resistors can handle 5W.
However, it is much safer to use resistors with a higher power rating than this, as any one of them could fail.
When wired in parallel, the total resistance remains the same, but the voltage is shared between all of them. For example, four 1 Ohm resistors in parallel will share the voltage and each experience a quarter of it, however the total resistance is still only 1 Ohm.
When resistors are wired in either series or parallel, you should use a multimeter to check the total resistance and power rating of the combination.
Switches are an essential part of any wiring system. They are used to allow the user to turn appliances on and off. Two common types of switches are ‘Momentary’ and ‘Holding’. The former is usually a small white rectangle with two or three prongs at the back and one long, flat prong at the front.
It is used to control lighting, such as lamps or light bulbs. The latter is usually a large grey rectangle with two or three prongs at the back and one short, flat prong at the front. It is used to control major appliances, such as a table-top oven or a radio.
When placing switches in a room, you should always place them next to doors so that users can turn the lights on and off when they enter or exit. You should also place them near the appliances they control, so that users can turn the appliance on and off without having to walk too far.
When wiring a momentary switch, you must connect the wires to the long, flat prong. When wiring a holding switch, you must connect the wire to one of the short, flat prongs. The other short, flat prong is not used and should not have a wire connected to it.
Wires are bundled together in what is called a ‘cable’. Cables can be made of various materials, each with their own pros and cons. The most common material is ‘insulated copper’, which has many advantages, such as being flexible and resistant to heat. However, it is usually the most expensive material.
Other cheaper materials include ‘un-insulated copper’ and ‘insulated steel’.
If insulated steel cables are used, they must be connected using steel clips. These clips are cheap and should be used whenever insulated steel cables are installed.
If you have any questions about wiring, please see me or another staff member.
Once you have gathered all of the materials needed, you may begin. Begin by placing the power cell in a secure location, such as a locked metal box. Then, drill a hole through the floor and pass an insulated copper cable from the cellar and up into the wiring chamber.
Now, you must decide how to connect the system to the power cell. You must either connect all of the appliances in the room to the power cell, or you can leave the power cell disconnected and run a ‘mated’ cable, with both insulated copper and fibre-optic cables inside, from the wiring chamber to the power cell. You must also decide whether the holding switch should be connected to the power cell or to the room. Please see diagrams below for details.
Important: Do not attempt this project without supervision. Wiring a room is very dangerous. If you feel uncomfortable performing any part of this project, please see a staff member.
The Electrical System was designed and written by: Ben Fleming
Please contact me if you find any grammatical or spelling mistakes!
Thank you to my friends and fellow teachers at the International School of Beijing, who helped test-run this project.
Sources & references used in this article:
Best Multimeter for Electricians: Top 6 of 2020 by E Mentor – 2017 – electricianmentor.com
DT830D Cost-Effective Digital Multimeters by BFRB Accuracy, DC Current, C Buzzer, LCD Size… – weclonline.com
Microprocessor multimeters based on digital processing of the instantaneous values of signals by VV Stadnik, VN Chinkov – Measurement Techniques, 1995 – Springer
Acquisition Signals from Electromagnetic Field-Meters Using Digital Multimeters with Event Logging Mode by D Belega, C Dughir – Proceedings of the XIX IMEKO World Congress …, 2009 – Citeseer