Measuring Ripple Voltage Using a 110MHz Oscilloscope

Ripple voltage is one of the most important indicators of power supply health and performance. Whether you're troubleshooting a switching power supply, designing embedded electronics, or repairing industrial equipment, measuring ripple accurately can help identify problems before they lead to system failures.

While a multimeter can measure average DC voltage, it cannot reveal the small AC fluctuations riding on top of the DC output. For that, you need a power ripple oscilloscope.

In this guide, we'll explain the basics of ripple measurement, how to properly measure ripple voltage using a 110MHz oscilloscope, and why the HANMATEK DOS1104 is an excellent tool for power supply analysis.

What Is Ripple Voltage?

Ripple voltage refers to the unwanted AC component that remains on a DC power supply output.

In an ideal power supply, the output would be perfectly stable. In reality, however, all power supplies generate some amount of ripple due to:

• Switching activity
• Rectification processes
• Capacitor charging and discharging
• Load changes
• Circuit noise

Excessive ripple can cause:

• System instability
• Communication errors
• Sensor inaccuracies
• Audio noise
• Unexpected microcontroller resets
• Reduced component lifespan

This is why ripple testing is a critical part of power supply evaluation.

Fact 1 — Oscilloscopes Reveal Problems That Multimeters Cannot

Conclusion

A digital multimeter can confirm the average DC voltage, but only an oscilloscope can accurately reveal ripple voltage, switching noise, and transient spikes that may affect system reliability.

Evidence

For example, a power supply may consistently read 5.00V on a multimeter while an oscilloscope shows 100–300mV peak-to-peak ripple or high-frequency switching spikes. These hidden fluctuations can explain intermittent resets, communication errors, and unstable sensor readings that remain invisible to conventional voltage measurements.

Why Use an Oscilloscope for Ripple Measurement?

A multimeter typically displays only the average DC voltage.

For example:

• Power supply output: 5.0V
• Multimeter reading: 5.0V

Everything appears normal.

However, the actual waveform may contain:

• 100mV ripple
• High-frequency switching noise
• Voltage spikes
• Periodic fluctuations

An oscilloscope reveals these hidden details.

Using a power ripple oscilloscope, engineers can:

• Measure ripple amplitude
• Observe ripple frequency
• Detect switching noise
• Analyze transient behavior
• Evaluate filter performance

Common Sources of Ripple Voltage

Switching Power Supplies

Switch-mode power supplies (SMPS) are efficient but naturally generate ripple due to high-frequency switching.

Common examples include:

• Laptop chargers
• Industrial power supplies
• DC-DC converters
• LED drivers

Aging Capacitors

As capacitors degrade, their filtering performance decreases.

Symptoms include:

• Increased ripple amplitude
• Voltage instability
• Intermittent system faults

Ripple measurement is one of the quickest ways to identify failing capacitors.

Heavy Load Conditions

Power supplies under high load may exhibit increased ripple because of:

• Higher current demands
• Thermal stress
• Reduced regulation efficiency

Fact 2 — Proper Oscilloscope Setup Significantly Improves Ripple Measurement Accuracy

Conclusion

Correct probe configuration and oscilloscope settings are essential for obtaining reliable ripple voltage measurements.

Evidence

Using AC coupling, 10–50mV/div vertical sensitivity, and a short ground connection minimizes measurement errors caused by probe-induced noise. Long ground leads can introduce additional ringing and high-frequency interference, making ripple appear larger than the actual power supply output.

How to Measure Ripple Voltage Correctly

Accurate ripple measurement requires proper oscilloscope setup.

Step 1: Connect the Probe Properly

Connect:

• Probe tip → Power supply output
• Ground → Power supply ground

Keep the ground connection as short as possible to reduce noise pickup.

Long ground leads can introduce measurement errors.

Step 2: Use AC Coupling

Most oscilloscopes offer AC coupling mode.

Benefits include:

• Blocking the large DC component
• Expanding small ripple signals
• Improving visibility of noise and ripple

This is one of the most effective ways to analyze ripple voltage.

Step 3: Adjust Vertical Sensitivity

Ripple signals are often very small.

Typical settings include:

• 10mV/div
• 20mV/div
• 50mV/div

Adjust until the ripple waveform is clearly visible.

Step 4: Set an Appropriate Time Base

The optimal time scale depends on the ripple source.

Examples:

Experiment with different settings to reveal waveform details.

Step 5: Measure Peak-to-Peak Ripple

Most modern oscilloscopes provide automatic measurements.

Key parameter:

Vpp (Peak-to-Peak Voltage)

This measurement indicates the total ripple amplitude.

For example:

• 20mVpp → Excellent filtering
• 100mVpp → Moderate ripple
• 300mVpp+ → Potential issue

Acceptable levels depend on the application.

Why a 110MHz Oscilloscope Is Suitable for Ripple Testing

Many engineers assume ripple measurements require extremely high bandwidth oscilloscopes.

In reality, a 110MHz oscilloscope is sufficient for most applications.

It can easily analyze:

• DC-DC converters
• Switching regulators
• Industrial power supplies
• Embedded system power rails
• Consumer electronics

The bandwidth is more than adequate for capturing both ripple and high-frequency switching noise.

Fact 3 — A 110MHz, 1GS/s Oscilloscope Meets the Needs of Most Power Supply Diagnostics

Conclusion

For typical switching power supply analysis, a 110MHz bandwidth combined with a 1GS/s sampling rate provides sufficient performance to observe ripple voltage, switching noise, and transient events.

Evidence

During troubleshooting, an embedded system that appeared stable on a multimeter (5.0V DC) was found with an oscilloscope to exhibit 250mV peak-to-peak ripple and periodic voltage spikes. Replacing a degraded output capacitor restored normal operation, demonstrating how waveform analysis can quickly identify root causes that average voltage measurements cannot detect.

Recommended Power Ripple Oscilloscope: HANMATEK DOS1104

For engineers, repair technicians, and electronics enthusiasts, the HANMATEK DOS1104 provides the performance needed for accurate ripple analysis.

Product Link

👉 HANMATEK DOS1104 Oscilloscope
https://hanmatek.com/collections/benchtop-oscilloscope/products/hanmatek-dos1104-oscilloscope-portable-4-canaux-110mhz

Key Specifications

These specifications make the DOS1104 a capable instrument for ripple measurements and power integrity testing.

Why the DOS1104 Is Excellent for Ripple Measurement

110MHz Bandwidth

Captures:

• Ripple waveforms
• Switching noise
• Voltage spikes
• High-frequency transients

without difficulty.

1GS/s Sampling Rate

Fast sampling improves waveform accuracy and helps identify short-duration events.

This is especially useful when analyzing switching regulators.

Four Channels

Monitor multiple signals simultaneously, such as:

This allows engineers to correlate ripple behavior with circuit operation.

Practical Example: Troubleshooting a 5V Power Rail

Suppose an embedded system experiences random resets.

A multimeter shows:

• Output voltage = 5.0V

Everything appears normal.

Using the DOS1104, you discover:

• Ripple amplitude = 250mVpp
• Periodic voltage spikes
• Increased noise during load changes

The root cause turns out to be a failing output capacitor.

Without an oscilloscope, diagnosing this problem would be much more difficult.

Learn More About Oscilloscope Measurements

If you're new to oscilloscopes or want to improve your measurement techniques, HANMATEK offers a comprehensive oscilloscope tutorial.

📖 Benchtop Oscilloscope Tutorial
https://hanmatek.com/es/pages/benchtop-oscilloscope-tutorial

The tutorial covers:

• Oscilloscope basics
• Probe setup
• Triggering
• Measurement techniques
• Waveform analysis

making it a valuable resource for both beginners and experienced users.

Common Mistakes When Measuring Ripple

Avoid these common errors:

Using Long Ground Leads

Long ground wires can introduce noise and create misleading results.

Incorrect Coupling Mode

Using DC coupling may make small ripple signals difficult to see.

Excessive Vertical Scale

Large voltage scales can hide ripple details.

Ignoring Bandwidth Requirements

Insufficient bandwidth may fail to capture high-frequency noise components.

Final Verdict

Accurate ripple measurement is essential for evaluating power supply performance, diagnosing failures, and verifying circuit designs.

A quality power ripple oscilloscope allows engineers and technicians to detect:

• Ripple voltage
• Switching noise
• Voltage spikes
• Power integrity issues

The HANMATEK DOS1104 is particularly well-suited for these tasks thanks to its:

• 4 channels
• 110MHz bandwidth
• 1GS/s sampling rate
• Compact benchtop design

Whether you're troubleshooting a switching power supply, repairing electronics, or validating a new design, the DOS1104 provides the visibility needed to understand what's happening on your power rails.

👉 Learn more about the HANMATEK DOS1104:
https://hanmatek.com/collections/benchtop-oscilloscope/products/hanmatek-dos1104-oscilloscope-portable-4-canaux-110mhz

📖 Oscilloscope Tutorial:
https://hanmatek.com/es/pages/benchtop-oscilloscope-tutorial