Why Verify Your Oscilloscope?

Oscilloscopes are critical instruments for debugging analog and digital signals. Over time, component aging, temperature variation, or accidental overloads can affect their accuracy. While full calibration requires certified equipment, you can still conduct DIY oscilloscope verification to assess key parameters — especially for older or lab-owned scopes without active service plans.

What You Can Verify Yourself

DIY verification does not replace factory calibration but helps detect drift or degradation. You can verify:

• Vertical accuracy: Measure known voltage levels
• Timebase accuracy: Verify horizontal scale using a precise frequency
• Bandwidth check: Use a fast pulse rise-time or high-frequency sine wave
• Trigger stability: Evaluate jitter, missed triggers, or instability
• Probe compensation: Confirm probe RC compensation matches scope input

Tools Needed for DIY Verification

• Function Generator: To provide stable sine, square, and ramp signals (1 Hz to 10 MHz range)
• DC Reference Source: A stable low-noise voltage source (e.g., 1 V, 5 V)
• Counter or Frequency Reference: GPSDO or rubidium standard if you check timebase in detail
• 50 Ω Terminator & Attenuators: For bandwidth and rise-time tests
• Calibration Fixture or Loopback Test Board: Optional, but improves repeatability

We recommend checking the Electronic Test & Instrumentation section for compatible signal sources and probes.

Verification Procedure

1. Vertical Scale Accuracy

Connect the DC reference to each channel, set scope input to 1x or 10x probe, and measure:

• Expected vs. measured voltage (±2% typical tolerance for most scopes)
• Noise floor at 0 V input

2. Timebase Accuracy

Feed in a 1 MHz sine wave from a calibrated signal generator. Compare measured period (1 µs/div expected) to theoretical value. Most scopes have a ±50 ppm to ±100 ppm spec.

3. Bandwidth & Rise Time

Inject a 10 MHz to 100 MHz square wave with fast rise time (≤1 ns) and compare the measured rise time to:

BW ≈ 0.35 / RiseTime

Check that your measured -3 dB point matches the manufacturer’s bandwidth (±10%).

4. Trigger Stability

Use the same sine wave to check if trigger locks consistently. Test for:

• Glitchy or missing triggers
• Waveform drift during multiple acquisitions

5. Probe Compensation

Use the built-in calibration square wave output (often 1 kHz) and verify square wave shape. Adjust probe trimmer capacitor until you see a flat top and sharp corners.

Acceptable Tolerances by Parameter

FAQs: Oscilloscope Verification

Can DIY verification replace calibration?

No. It helps detect faults but doesn’t offer traceability or official certificates.

How often should I verify my oscilloscope?

Every 6–12 months or after suspected overload, shock, or long storage.

Is rise time the same as bandwidth?

No, but they are related. Bandwidth ≈ 0.35 / Rise Time (approximation for Gaussian systems).

Conclusion

Even without formal calibration labs, regular DIY oscilloscope verification can help identify signal distortion, drift, or degraded inputs before they affect your work. By following the outlined steps and using common signal sources and DC references, you maintain confidence in your measurements. To find compatible signal generators and scope accessories, browse the Electronic Test & Instrumentation collection.