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Oscilloscope practice

Read voltage amplitude, peak-to-peak voltage, period, frequency and phase difference.

Practise

Frequency

Find the frequency in Hz of trace A. Give your answer to 3 significant figures.

Ideal sinusoidal voltage traces; one large square is one division. A is solid and B, when present, is dashed. Both channels have the same sensitivity and time-base.

Trace A has amplitude 1.5 divisions and period 4 divisions. Vertical sensitivity 0.5 V/div; time-base 0.5 ms/div.A solid0.5 V/div · 0.5 ms/div0 V
One large square is one division; the middle horizontal line is 0 V.
Diagram text alternative

Trace A has amplitude 1.5 divisions and period 4 divisions. Vertical sensitivity 0.5 V/div; time-base 0.5 ms/div.

Larger diagram
Trace A has amplitude 1.5 divisions and period 4 divisions. Vertical sensitivity 0.5 V/div; time-base 0.5 ms/div.A solid0.5 V/div · 0.5 ms/div0 V

Treat the given values as exact unless an uncertainty is stated.

Use decimals or e notation, e.g. 4.2e-3. Enter the unit separately.

Hint

Measure one complete cycle, multiply by ms/div, then convert milliseconds to seconds. For frequency, use f = 1/T.

Worked solution
  1. T = 4 × 0.5 = 2 ms = 0.002 s.
  2. f = 1/T.
  3. Answer: 500 Hz (3 significant figures).
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Question type: Mixed practice
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Voltage and time scales

Multiply vertical divisions by volts per division. Amplitude runs from the zero line to a peak; peak-to-peak spans both extremes. Multiply horizontal divisions for one complete cycle by the time-base. Convert ms to s before using f = 1/T.

Phase difference

For traces of the same frequency, use corresponding rising zero crossings or matching peaks. Phase magnitude = horizontal shift / period span × 360°. The dashed trace B is shifted right and lags A here. A half-cycle shift is 180°; at that limit leading and lagging are equivalent descriptions.

These are ideal sinusoidal signals with a shared sensitivity and time-base. Triggering, probe attenuation, offsets, noise and rms voltage are outside these tasks.

A-level relevance

AQA 7408: 7.1 AT h (selected); AQA 7408: 3.3.1.1 (selected); OCR A H556: 1.2.2(h); 4.4.1(b–c) (selected). Tasks cover the selected skills listed above.

AQA specification · AQA specification · OCR A specification · AQA practical handbook · OCR practical skills handbook

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