But if you're new to the world of digital multimeters, it can be overwhelming to choose the right one and learn how to use it effectively. That's why we've created the ultimate beginner's guide to digital multimeters. In this guide, we'll cover everything you need to know about digital multimeters, including their features, how to use them, and why they're so important. So, whether you're a beginner or an experienced user, read on to discover the power of digital millimeter’s and why you need one in your toolkit.
A multimeter is an essential tool for measuring electrical parameters like resistance, voltage, and current. When it comes to measuring resistance, the multimeter uses a simple principle known as Ohm’s Law. Ohm’s Law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor.
In other words, if we know the voltage and current flowing through a conductor, we can calculate the resistance using Ohm’s Law.
A step by step guide to understanding digital multimeter
To begin with, first let's get ourselves into knowing which parameters are supported by a digital multimeter, lets look at the picture below so that you can understand what I am talking about:
As you can see from the above picture; we have the adjustment knob set at OFF state, meaning the multimeter is switched off.
Around the adjustment knob is the parameters that the digital multimeter is capable of measuring. Starting from AC voltage marked with V~ ranging from (200m-750) to DC voltage marked with V- ranging from (200m-1000), AC/DC current marked with A~ and A- respectively ranging from (200m-20). The digital multimeter also measures capacitance, look for Farads ranging from (200μ-20Π), resistance marked with sign Ω ranging from (200-200megaohms) and finally but not least diodes.
Now let see how the multimeter can be used to measure each one of this parameters;
Let's start with resistance.
To illustrate examples of how resistance is measured using a multimeter, let’s consider a simple circuit consisting of a resistor and a battery.
First, we need to set the multimeter to the resistance mode and select the appropriate range. Next, we need to connect the multimeter leads across the resistor, making sure that the polarity is correct. The multimeter will then display the resistance value of the resistor in ohms.
Another example could be measuring the resistance of a wire or cable. In this case, we need to disconnect the wire from the circuit and make sure it is not connected to any power source. We then connect the multimeter leads across the wire, and the multimeter will display the resistance value of the wire in ohms. This is useful for testing the continuity of wires and verifying their integrity.
There are other methods of measuring resistance e.g; by color codding but measuring resistance using a multimeter is a simple process that involves connecting the multimeter leads across the conductor and reading the resistance value on the display. By using this technique, we can quickly and accurately measure the resistance of various electrical components and circuits.
Now let's look at capacitance.
The capacitance of a capacitor is measured in farads (F), and it is essential to know the capacitance value of a capacitor to determine its suitability for various electrical applications. Measuring capacitance can be done using various techniques, but one of the most common methods is using a digital multimeter.
To measure capacitance using a digital multimeter, you need to select the capacitance measurement mode from the device’s menu. After selecting the mode, connect the capacitor leads to the multimeter’s probes and wait for the multimeter to stabilize. The multimeter will then display the capacitance reading in farads or microfarads, depending on the capacitor’s size.
For example, let’s say you have a 100 microfarad capacitor that you want to measure using a digital multimeter. You would first connect the capacitor leads to the multimeter’s probes and select the capacitance measurement mode. The multimeter would then display the capacitance value of the capacitor, which in this case, would be 100uF.
Another example of measuring capacitance with a digital multimeter is when testing the capacitance of a printed circuit board (PCB). In this case, you would first isolate the PCB from the power source and discharge any residual charge in the capacitor. Then, connect the multimeter’s probes to the capacitor leads and select the capacitance measurement mode. The multimeter would then display the capacitance value of the capacitor, which you can compare with the expected value to determine the capacitor’s health.
Measuring capacitance using a digital multimeter is a straightforward process that requires selecting the capacitance measurement mode, connecting the capacitor leads to the multimeter’s probes, and waiting for the multimeter to display the capacitance reading. This technique is useful in various electrical applications, including testing capacitors and printed circuit boards.
Measuring diodes
Measuring diodes with a digital multimeter is a common task for electronics professionals and hobbyists alike. Diodes are essential components in electronic circuits, serving as one-way valves for current flow. Measuring diodes accurately can help diagnose problems with a circuit and ensure that a replacement diode is compatible.
To measure a diode with a digital multimeter, the device should be set to the diode testing mode. In this mode, the multimeter sends a small current through the diode and measures the voltage drop across it. A good diode will show a voltage drop of around 0.6-0.7 volts, while a faulty or damaged diode will show a much higher voltage drop or no voltage drop at all.
For example, let’s say you are working on a circuit that is not functioning properly. You suspect that one of the diodes may be faulty. To test this, you would set your digital multimeter to the diode testing mode and place the red lead on the anode side of the diode and the black lead on the cathode side. If the multimeter shows a voltage drop of around 0.6-0.7 volts, the diode is likely functioning properly. If the multimeter shows a higher voltage drop or no voltage drop, the diode is likely faulty and should be replaced.
Measuring diodes with a digital multimeter is a simple yet important task for anyone working with electronic circuits. By following the proper procedures and interpreting the results correctly, you can diagnose problems and ensure that your circuits are functioning at their best.
Measuring AC/DC current and voltage
To measure AC/DC voltage, you need to set the DMM to the voltage mode and select either AC or DC as per the type of voltage you want to measure. Once the mode is selected, connect the probes to the voltage source, ensuring that the polarity is correct. The display will show the measured voltage in volts.
 |
| AC voltage |
 |
| DC voltage |
Similarly, to measure AC/DC current, you need to set the DMM to the current mode and select either AC or DC as per the type of current you want to measure. However, before connecting the probes, you need to ensure that the circuit is broken and the current-carrying wire is connected to the DMM in series. Once the probes are connected, the DMM will measure the current flowing through the circuit and display it in amperes.
 |
| AC current |
Note if you're measuring current you need to change the probe to amperes mode, by just moving the red probe from V/Ω to 20A port or mA considering the current you want to measure. Above is an example of how to measure AC current.
For example, if you want to measure the voltage across a battery, you need to set the DMM to DC voltage mode and connect the red probe to the positive terminal and the black probe to the negative terminal of the battery. Similarly, if you want to measure the current flowing through a resistor, you need to set the DMM to DC current mode, break the circuit, and connect the probes in series with the resistor.
In conclusion, the process of measuring AC/DC voltage and current with a digital multimeter is simple and straightforward. However, it is essential to follow the correct procedure and ensure that the polarity and connections are correct to get accurate readings.
Comments
Post a Comment