CH1
- Frequency
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- Period
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- RMS
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- Mean
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- Maximum
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- Minimum
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- Peak-to-peak
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- Rise time (10–90%)
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- Fall time (90–10%)
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- Duty cycle
- —
Virtual engineering lab
Oscilloscope Fundamentals
Practice two-channel oscilloscope setup, scaling, triggering, cursors, coupling, and automatic waveform measurements using deterministic reference signals.
Electrical Engineering / InstrumentationintroductoryValidated educational model
0% complete0 / 0 requirements
Complete the procedure, collect the required measurements, pass the engineering validation, and answer every graded concept question correctly.
What you should establish
- Set vertical scale and offset independently for two oscilloscope channels.
- Choose a timebase that displays enough waveform detail for reliable measurement.
- Configure trigger source, level, mode, and slope to stabilize a periodic waveform.
- Use time and voltage cursors to make manual measurements.
- Compare automatic frequency, RMS, mean, extrema, peak-to-peak, rise/fall time, and duty-cycle measurements with known reference signals.
Work through the experiment
Collect evidence from the model
- CH1 frequencyFrequency estimated from acquired CH1 threshold crossings.Pending
- CH1 periodAverage period measured from CH1 rising crossings.Pending
- CH1 RMSRoot-mean-square value of the displayed CH1 samples.Pending
- CH1 peak-to-peakMaximum minus minimum CH1 sample voltage.Pending
- CH2 frequencyFrequency estimated from acquired CH2 threshold crossings.Pending
- CH2 duty cycleFraction of acquired CH2 time above its midpoint.Pending
Verify the result, not just the workflow
- Reference frequency checkCompares the acquired CH1 frequency with the configured reference frequency.Pending
- Reference amplitude checkCompares acquired CH1 peak-to-peak voltage with the configured sine amplitude.Pending
Only a passed engineering check satisfies guided completion. Warnings and failures remain visible even if the procedure checklist is complete.
Answer the graded multiple-choice questions
Choose one answer for each question. Each selection is graded immediately and saved locally. Guided Lab completion requires every concept question to be correct.
Concept score: 0 / 4 correct
Virtual instrument
Auto · waitingTwo-channel digital oscilloscope
Run the experiment to acquire the reference signals.
Automatic waveform measurements
CH2
- Frequency
- —
- Period
- —
- RMS
- —
- Mean
- —
- Maximum
- —
- Minimum
- —
- Peak-to-peak
- —
- Rise time (10–90%)
- —
- Fall time (90–10%)
- —
- Duty cycle
- —
Measurements
Instrument readings
- CH1 frequency
- — Frequency estimated from acquired CH1 threshold crossings.
- CH1 period
- — Average period measured from CH1 rising crossings.
- CH1 RMS
- — Root-mean-square value of the displayed CH1 samples.
- CH1 peak-to-peak
- — Maximum minus minimum CH1 sample voltage.
- CH2 frequency
- — Frequency estimated from acquired CH2 threshold crossings.
- CH2 duty cycle
- — Fraction of acquired CH2 time above its midpoint.
Result visualization
Acquisition and cursor checks
Use these numerical acquisition readouts to verify what the graticule shows. Cursor values remain available even when color perception or display size makes the waveform harder to inspect.
- Acquisition window
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- Sample rate
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- Trigger
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- Cursor Δt
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- Cursor 1/Δt
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- Cursor ΔV
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A useful manual check is to place the two time cursors one period apart. The reciprocal of Δt should agree with the automatic frequency measurement within cursor-placement resolution.
Theory
Equations and model
Vertical scale
Volts/div determines how much input voltage corresponds to one vertical graticule division. A signal that is clipped off-screen needs a larger volts/div setting; a very small trace needs a smaller setting.
display divisions = signal voltage / (volts/div)Timebase and sampling
Time/div determines the horizontal acquisition window. Ten horizontal divisions are displayed. The virtual scope samples the entire window deterministically, then derives measurements from those samples rather than from the reference signal parameters.
window time = 10 · time/divsample rate = sample count / window timeTriggering
The trigger starts a stable acquisition when the selected channel crosses the trigger level in the selected direction. Auto mode still displays an acquisition when no valid crossing is found; Normal mode reports the missing trigger so students can diagnose the setup.
Automatic measurements
Frequency and period are estimated from threshold crossings. RMS, mean, minimum, maximum, peak-to-peak, duty cycle, and 10–90% rise/fall times are calculated from the acquired samples.
Validation
Independent checks
Reference frequency checkNot run
Compares the acquired CH1 frequency with the configured reference frequency.
- Expected
- —
- Simulated
- —
- Error
- —
- Tolerance
- 0.5%
Run the experiment to perform this check.
Reference amplitude checkNot run
Compares acquired CH1 peak-to-peak voltage with the configured sine amplitude.
- Expected
- —
- Simulated
- —
- Error
- —
- Tolerance
- 0.5%
Run the experiment to perform this check.
Engineering interpretation
Run the experiment to generate an engineering interpretation.
Assumptions and limitations
Assumptions
- Reference signals are deterministic and ideal during Phase 1.2.
- The acquisition uses uniformly spaced samples across a ten-division horizontal window.
- This fundamentals experiment keeps ideal acquisition for control-learning clarity. The shared Phase 1.7 error engine now covers generic noise, calibration offset, and quantization; probe loading, analog bandwidth, clipping, and aliasing remain hardware-specific future effects.
- AC coupling is represented by removal of the acquired mean value rather than a detailed coupling-network transfer function.
Limitations
- The Phase 1.2 scope is an educational instrument model, not a hardware-specific oscilloscope emulator.
- Protocol decoding, FFT, XY mode, bandwidth limiting, probe attenuation error, persistence, and segmented acquisition are future capabilities.
- The Oscilloscope Fundamentals experiment intentionally retains a fixed calibration pair; the Phase 1.3 Function Generator Fundamentals experiment connects the reusable generator directly to CH1.
Local experiment export
Phase 1.9Save your measurements and setup
Exports are generated in your browser. No account or server upload is required.
- Settings JSON
- Current parameter values for reproducibility and later project handoff.
- Measurements CSV
- Completed instrument readings with labels, units, and descriptions.
- Plot PNG
- The current canvas-based scope, transient, sweep, or statistics visualization when available.
- Summary
- Markdown report with objectives, setup, measurements, validation, interpretation, assumptions, and graded guided concept-check results.
Ready to export the current local experiment state.
What this experiment should establish
- Set vertical scale and offset independently for two oscilloscope channels.
- Choose a timebase that displays enough waveform detail for reliable measurement.
- Configure trigger source, level, mode, and slope to stabilize a periodic waveform.
- Use time and voltage cursors to make manual measurements.
- Compare automatic frequency, RMS, mean, extrema, peak-to-peak, rise/fall time, and duty-cycle measurements with known reference signals.
Questions to answer from the experiment
- What happens to automatic frequency measurement if the timebase shows less than one complete period?
- Why does moving the trigger level outside the waveform amplitude prevent a normal trigger?
- Why does AC coupling remove the CH1 DC offset while preserving most of the periodic waveform?
- How does cursor placement error affect a manually calculated frequency from 1/Δt?