Whether you're troubleshooting a battery-powered device or building a simple circuit, knowing how to measure DC voltage is essential. In this guide, we’ll walk you through exactly how to do that using the Fluke 101 digital multimeter—a compact, reliable tool perfect for everyday electrical tasks.

What Is DC Voltage?

DC stands for Direct Current, and it’s the type of electricity that flows in one direction—like water running through a hose. You'll find DC power in:

• Batteries (AA, 9V, lithium-ion, etc.)
• Solar panels
• Most electronic devices (phones, laptops, remotes)

DC voltage is represented by this symbol on your multimeter:

V⎓

(a V with a straight line and dashed line underneath)

 How to Set Up the Fluke 101 for DC Voltage Testing

1. Insert the probes:

• • Plug the black lead into the COM terminal.
  • Plug the red lead into the terminal marked V (for voltage).

2.Select the DC Voltage mode:

• • Turn the rotary dial to the DC voltage setting. On the Fluke 101, it’s marked as V⎓.

• The Fluke 101 is auto-ranging, so you don’t need to select the voltage range—it does the work for you.

Measuring a Battery

To test a battery:

• Touch the red probe to the positive terminal (+).
• Touch the black probe to the negative terminal (–).

The screen will instantly show the voltage.
If you see a negative number, no worries—it just means you have the probes reversed. Swap them and you’re good.

Example: Testing a Voltage Divider Circuit

Say you’ve built a simple voltage divider with resistors. When you place your probes across part of the circuit:

• You might see something like 0.031V, or 31 millivolts.

Even though that’s a small value, the Fluke 101 will still display it accurately in volts.
While the multimeter does have an AC millivolt mode, it does not support DC millivolts—so just read the small DC values in volts (e.g., 0.031V) and mentally convert to millivolts if needed.

 What If You Have a Manual Range Multimeter?

Some multimeters require you to manually select a voltage range. Here’s how:

• If your battery is 12V, pick the 20V range.
• If it’s 1.5V, pick the 2V range.
• If you're unsure, start from the highest range and work your way down until the screen shows a meaningful number.

Measuring Voltage Inside a Circuit

With the Fluke 101, you can also check voltages at various points inside a powered circuit:

• Measure between the positive and negative terminals to see total voltage.
• Probe across individual components (like resistors or LEDs) to observe voltage drop.
• 📌 Just remember:
  The circuit must be powered on, and you’re always measuring the difference in voltage between two points. If you probe the same point, you'll see zero—because there’s no difference!

 A Quick Note About AC Voltage

Your home outlets supply AC voltage (Alternating Current), which is very different from DC. AC alternates direction—like ocean tides—so when viewed on an oscilloscope, it looks like a sine wave, unlike the straight line you’d see from a battery.

The Fluke 101 can also measure AC voltage, but that’s a topic for another day!

✅ Final Tips

• Always start with DC voltage mode when working with batteries and electronics.
• If the reading is negative, simply swap the probes.
• The Fluke 101’s auto-range feature makes it one of the easiest tools for quick voltage checks.

Ready to get started?
Grab your Fluke 101 multimeter and test the batteries around your home—you’ll be surprised how empowering this little skill can be.

Need a Fluke 101 or replacement probes? [Shop now →]