How to Use a DT830B Digital Multimeter to Test Voltage and Amps

In this tutorial and review, you will see how to use a cheap DT830B digital multimeter to measure the voltage and amperage of a computer fan. Please watch the video to see how to use this digital multimeter.

DC Voltage measurement using a DT830B multimeter

Firstly, let’s see how to use the DT830B digital multimeter to read the voltage of any electronics. In this example, I’m using a 12V DC power supply with a DC connector to plug the computer fan. On the DT830b multimeter, place the red probe in the V, W, mA port of the power supply and put the black probe in the COM port. 

Check this DT830B Digital Multimeter on Amazon

To read the voltage of the DC power supply, you can turn on the digital multimeter and select the appropriate reading mode. You can select either 200m, 2000m, 20, 200 or 1000V. The value selected should be higher than the value expected. For example, if you want to test the voltage in a circuit powered by a 1.5V battery you can select the 2000m reading mode on the multimeter. On the other hand, for a 12V battery, you should select 20V. In my example, I’m using a 12V DC power supply so I should select the DCV20 reading mode on the multimeter. 

You can now read the voltage of this power supply. Put the black probe of the multimeter on the negative end (-) of the connector and the red probe to the positive side (+). You can measure directly the voltage using the digital multimeter since you don’t have to disconnect the fan while you do the readings. I measured here 12.15V for my power supply, which roughly corresponds to the datasheet.

Check this Digital Multimeter DT830B on AliExpress

Amperage measurement using a DT830B multimeter

It is a bit more complex to measure the amperage. The amperage is the current drawn by an electronic device. To measure the amps, the fan should not be connected directly to the power supply. The actual connection is instead made through the digital multimeter. 

To read the amperage of any electronics, the red probe of the multimeter should be placed in the 10A port while the black probe should be connected to the COM port. You can select the 200u, 2000u, 20m, 200m or 10A value depending on the specifications of your electronic devices. For example, this computer fan is rated 0.25 amp, which is 250mA. Since this value exceed the 200m, I will thus select the 10A reading mode on the multimeter. 

Now, I can test the amperage of this fan. Always disconnect the power supply until you are ready to use the digital multimeter as you don’t want to end up with an electric shock. You should connect the black wire of the electronic device (fan) in the negative port of the power supply connector. The red wire of the fan is twisted around the black probe of the DT830B multimeter. You are now ready to connect the power supply and apply the red probe of the multimeter to the positive end of the power supply. I’m getting a value of 0.23 A, which corresponds to the datasheet of the computer fan.

About the DT830B multimeter

In summary, the DT830B digital multimeter is the cheapest that you could find and they are easy to find online. These digital multimeters are reliable and also have a good accuracy. Hence, it is an must have item for the beginner’s electronic toolkit. It’s easy to use and it will certainly help you for any electronic project. You can also check this DT830B tutorial on Instructables. Please visit the wikipedia page for multimeters for more useful information.

Check my previous post to see how to make an ATX power supply using a breakout board or to see how to build a homemade humidifier using an ultrasonic mist maker.

Warning and disclaimer

Electrical current can cause serious injuries or death. I am not responsible for any accidents or damages. Feel free to use the affiliated links presented on this page. The prices are the same, it is anonymous, and this way you can support the making of these videos.