Voltage is perhaps the simplest and the most commonly read measurement in a multimeter. While reading DC voltage might appear easy on the surface, it takes in-depth knowledge of this single function for you to get good readings.
In short, you can measure the DC voltage with a multimeter by following these steps. First, switch the dial to DC Voltage. Next, put the black probe inside the COM jack and the red probes inside the V Ω jack. Next, remove the red probe first and then the black probe. Next, connect the test probes to the circuit. You can now read the voltage measurement in the display.
If you are a beginner who wants to know how to measure DC voltage with a Multimeter – both a digital and analog Multimeter, you’ve come to the right place. We will teach you the entire process, including how to analyze the results.
What is DC Voltage?
For understanding purposes, DC Voltage is the short form of the term direct current voltage – a voltage capable of producing DC. On the other hand, AC voltage is capable of producing an AC, alternating current.
In general reference, DC is used to define systems with constant polarity. However, in this context, DC is largely used to refer to quantities whose polarity doesn’t change regularly or the ones with zero frequency. Quantities that change polarity regularly at an above-zero frequency are called AC.
The voltage potential difference/unit charge between two positions in an electrical field is voltage. The movement and presence of charged particles (electrons) produce electrical energy. (1)
Voltage potential difference occurs when electrons move between two points – from a low potential point to a high potential point. AC and DC are the two types of electrical energy. (2)
The voltage derived from DC is the one we are discussing here – the DC voltage.
Examples of direct current sources include batteries, solar panels, thermocouples, DC generators, and DC power converters for rectifying the AC.
How to Measure DC Voltage with a Multimeter (Digital)
- Switch the dial to DC Voltage. If your digital multimeter comes with DC millivolts and unsure which one to select, begin with DC voltage as it accommodates higher voltage.
- Next, put the black probe inside the COM jack.
- The red probes should go inside the V Ω jack. Once you’ve done that, remove the red probe first and then the black probe.
- The fourth step entails connecting the test probes (black probes to the negative polarity test point and red to the positive polarity test point) to the circuit.
Note: You should know that most modern multimeters can automatically discover polarity. When using digital multimeters, the red lead doesn’t need to touch the positive terminal or the black lead to touch the negative terminal. If the probes contact the opposite terminals, you will see a negative symbol on display.
When using an analog multimeter, you must ensure that leads touch the right terminals lest you damage the meter.
- You can now read the voltage measurement in the display.
Useful Pointers When Measuring DC Voltage Using Digital Multimeter
- Modern digital multimeters are usually auto-range on default, depending on the function showing on the dial. You can change the range by pressing the ‘Range’ button several times until you achieve the desired range. The voltage measurement might fall within the lower dc millivolts setting range. Don’t worry. Remove the test probes, switch the dial setting to read dc millivolts, reinsert the test probes, and then read the voltage measurement.
- To obtain the most stable measurement, press the ‘hold’ button. You will see it upon completing the voltage measurement.
- Press the ‘ MIN/MAX ‘ button to obtain the lowest and highest DC Voltage measurement, press the ‘MIN/MAX’ button. Wait to hear a beep each time your digital Multimeter records a new voltage reading.
- If you wish to set the digital Multimeter to a predetermined value, hit the ‘REL’ (relative) or ‘?’ (Delta) buttons. The display will show voltage measurements below and above the reference value.
How to Measure DC Voltage with an Analog Multimeter
Follow these simple steps:
- Press the ‘ON’ button of your meter to turn it on.
- Rotate the Multimeter’s knob to “VDC” – DC voltage. If your analog multimeter doesn’t have the “VDC,” check if there is a V with a 3-dotted straight line and turn your knob to it.
- Go on to set the range, which should be bigger than the anticipated testing voltage range.
- If you are operating with an unknown voltage, the set range should be the highest possible.
- Connect the black probe to the COM socket and the red probe to the VΩ socket (preferably the one with the abbreviations VDC on it).
- Put the black probe on either a negative or lower voltage point and the red one on a positive or higher voltage point.
- To accomplish the maximum deflection, which helps increase accuracy, reduce your voltage range.
- Now take the readings on the VDC scale and be careful not to take the VAC scale reading.
- Once you’ve finished taking the readings, remove the red probe first and then the black probe.
- Turn off the Multimeter and then set the range to the maximum to prevent damage in case of quick reuse.
Unlike the digital multimeter, the analog multimeter doesn’t alert you when you get the polarity wrong, and this might result in meter damage. Be careful to always get the polarity right.
What Is An Overload Condition, And When Does It Happen?
There is a good reason why you are advised to select a voltage range higher than the anticipated value. Selecting a lower value could lead to an overload condition. A meter can’t measure the voltage when it surpasses its measurement range.
On a digital multimeter, you will know you are dealing with an overload condition if the Multimeter shows ‘out of range,’ ‘OL,’ or ‘1’ on the screen. Don’t panic when you get an overload indicator. It cannot harm or damage the Multimeter. You can overcome the condition by increasing the range with the selector knob until you achieve the anticipated reading. If you suspect a voltage drop within your circuit, you may also use a multimeter to measure it.
When using an analog multimeter, you’ll know you have an overload condition if you see ‘FSD’ (Full Scale Deflection) of the needle. In analog multimeters, overload conditions must be avoided to prevent possible damage. Stay clear of low voltage ranges when you don’t know the voltage measurement.
Safety Tip: avoid probes with broken or exposed wires. Besides adding error in a voltage measure reading, damaged probes are hazardous for measuring voltage.
Whether using a digital multimeter or analog multimeter, you now know how a Multimeter measures voltage. You can now confidently measure current.
If you give the process your full attention, you are good to go as far as measuring voltage from a DC source is concerned. Now, go on and measure voltage from your preferred DC source and see how it goes.
We’ve listed a few more learning guides on multimeter below. You may want to check and bookmark them for later reading. Thank you! And see you in our next article!
- How to check for battery drain with a multimeter
- How to use a multimeter to test the voltage of live wires
- Cen-Tech 7 function digital multimeter review
References
(1) electrons – https://whatis.techtarget.com/definition/electron
(2) electrical energy – https://www.sciencedirect.com/topics/engineering/electrical-energy
