So, how do you use a multimeter? Multimeters are cheap to buy, and they are one of the significantly used electronic test equipment. Although you will always get instructions when the test meter is bought, the further details on using a multimeter in testing circuits are not always available. Therefore, many individuals do not understand how to use a multimeter.
Some of the basic things that we measure include current and voltage. A multimeter is used for some sanity checks and troubleshooting. So is our circuit working? Does your switch work? To confirm this, just put a multimeter on it. This test meter remains your first company and defense when it comes to troubleshooting a problem.
What Are The Parts Of A Multimeter?
This device has three significant parts, which include:
Display – it usually has four digits, and it can display a negative sign. You will find that few multimeters have illuminated displays that provide better viewing in the situations where there are lowlights.
Selection Knob – selection knob allows the user to set the test meter to read various values like milliamps (mA) of current, resistance and voltage.
Ports – two probes are plugged into the two ports on the front of this unit. A multimeter has three ports. The first port is Com, which means common and this port is always connected to the ground of a circuit. The second port is 10A which is a special port because it deals with measuring large currents that are greater than 200mA. The last port is the mAVΩ which allows measurement of current up to 200mA, the voltage, and resistance. Voltage is represented by V and resistance is represented by Ω.
Main Steps To Using A Multimeter
1. Using Multimeter To Measure Resistance
Pick the resistor and set your multimeter to around the setting of 20kΩ.
After that, hold the probes against the legs of the resistor, just with a similar pressure amount. You should do this at the time you have begun to press the key on a keyboard.
In case you have done this successfully, you will notice a reading on the multimeter. It will read 0.00 or 1 or actual resistor value. If the multimeter reads one where it displays OL, then it is reloaded, so try another higher mode of around 200kΩ. Note that when one appears, there is no harm, but it only means that your range knob of the multimeter needs some adjustment. However, when it reads 0.00 or a figure which is nearly next to zero value, then you need to lower the mode to 2kΩ as fast as you can.
Note that, few of the resistors have a tolerance of 5% meaning that instead of the color codes indicating 10kΩ, it can indicate 9.5kΩ. This problem is a discrepancy in the manufacturing process.
Measuring resistance may not be perfect because various factors can affect the reading, for example, temperature. Also, when a device is physically installed in a circuit, it would be tricky to measure the resistance. The reason is that the reading can be affected by the surrounding components on the circuit board.
2. Measuring Current With Multimeter
So how do you measure current using the multimeter? Measuring current is tricky because you have to measure it in series. Remember voltage measuring is done in voltage but in this case of current, it is in the current. Therefore, to make it successful in estimating current, you will have to interrupt the current flow and then put the meter in-line.
So how do you do it?
- Have an extra piece of wire with you.
- Pull out the wire that goes to the resistor and adds your wire where the wire was connected. A probe from the power pin which is on the power supply to the resistor. By doing this, you will have ‘broken’ power to the circuit
- Then, insert the multimeter in-line so that the current is measured as it flows through your multimeter into the destined breadboard.
That is how easy you can do the measurement of current.
3. Measuring Voltage
Now you have the multimeter, and you also have to know how to measure alternating current voltage. In case you have a digital multimeter and the voltage in the circuit is not known, then you have to begin the process of measuring it:
- Turn your multimeter dial to V to mean voltage.
- Then insert the black lead into the common jack in the multimeter. Also, insert the red lead into the volt jack. When done with this process, begin removing the lead in reverse order – meaning you begin with the red one then the black.
- Try connecting the test leads to the circuit, starting with the black then the red one. Be careful that your fingers do not touch the lead tops.
- Now read the measurement which is displayed. When done, remove the leads beginning with the red. It is this simple.
For voltage measurements, the alternating current voltage will vary from one fluctuation to the other. So when it is from unexpected measurement, the voltage will be lower than the normal measurement.
4. How Can You Use The Meter To Test Continuity?
Testing for continuity is the testing of resistance between two points. If there is a low resistance, it means that the two points are electrically connected, and the meter will emit a tone. The continuity test helps in ensuring that the connections are all made accurately and correctly between two points. The test will as well help you to detect if two connected points that should not be are connected.
You can use your multimeter in testing for continuity:
- Just set the meter to the ‘continuity mode’ – this is a diode symbol with some propagation waves around it.
- Once you have set the meter to the continuity mode, now touch together with the probes. When you touch the probes, the meter should emit a tune. The tune shows that a small amount of current can flow without resistance (this is a very small resistance).
It would be expedient to know that not all meters have the continuity mode, but most should have it. So in case yours lacks the mode, it is fine because the meter can still work along with other lines of electrical duty.
Now that you are proficient and knowledgeable on how to use your multimeter, it is also significant to know few interventions in case the meters bring complications. The major complication is when you burn the meter’s fuse, so you have to know how to change it, and this is a very simple procedure.
5. Changing The Multimeter’s Fuse
A common problem with new meters comes when measuring current on a breadboard especially by probing from VCC to GND. At this point, it will short power to the ground through the meter causing the power on the board to blow out. So as this power rushes to the multimeter, it will cause the internal fuse to heat up and then burns out.
However, you have not to worry because replacing the fuse is simply just like this:
- Have you mini screwdriver and take out the meter’s screws.
- Also, do not forget the two screws that always hide behind the battery plate. Loosen them as well.
- Once all the screws are removed, begin to lift the face of the multimeter, slowly and slightly to avoid any breakage.
- You will notice the hooks on the bottom edge of the meter’s face. Here, you will have to apply some energy so as to slide the face sideways so as to disengage the hooks.
- Once you have succeeded in unhooking the face, the face will come out very easily, and you can view inside multimeter.
- Locate the fuse and lift on it and it will obviously pop out.
In correcting the fuse, you have to do it keenly and make sure you just replace the correct fuse with the correct type. A meter’s fuse is usually 200mA so your other fuse should also be 200mA fuse.
Protips About Using A Multimeter
Remember always to return the meter to its read voltage after using it. To make sure that the meter is back to the read voltage, just return the probes to the voltage port and set the meter such that it reads the Direct Current voltage range. If you leave your meter in its current mode, you will not be able to see the voltage on display next time you use the equipment.
The first time, you will, or you might realize that measuring current is tricky but just worry less about this even if you blow your fuse. You will have a better idea of how to replace the fuse later on.
Multimeters are usually easy to use, and you need this piece of test equipment in any electronic construction work you are undertaking. It is again fortunate that the instruction on how to use multimeter is also straightforward and simple to follow. Remember that with this kind of meter; you will be able to perform various types of tests, either using the older or the modern meters. So, are you ready to use the multimeter next time? Did the post serve your purpose when it comes to the knowledge of using multimeter? If yes, share the post.