The measurement handbook
Measurement guides
Connect carefully, capture deliberately and keep the limits of the measurement in view. Seven source-based guides for ordinary low-voltage electronics.
Bandwidth, sample rate and record length
Bandwidth limits the analogue signal that reaches the converter. Sample rate sets the spacing of captured points. Record length sets how long that rate can be maintained. Check all three in the channel and acquisition mode you will actually use.
Explore the guide Source-based guideAuto, normal and single trigger: catch the right event
Auto mode can draw a trace without a qualifying event. Normal mode waits for the trigger condition. Single acquisition stops after one qualifying capture. A blank or frozen display therefore needs a trigger check before it becomes evidence of a missing signal.
Explore the guide Source-based guideProbe loading, compensation and ground leads
A probe becomes part of the circuit. Its resistance changes DC loading, its capacitance increasingly loads fast signals, and its ground lead can introduce ringing. Compensate a compatible passive probe, use a short return path and repeat the measurement before blaming the circuit.
Explore the guide Source-based guideOscilloscope grounding and input limits
Many bench oscilloscope probe ground clips, BNC shells and channel references connect to protective earth and to one another. Connecting a ground clip to a live node can short that node to earth. Battery power alone does not prove that a handheld scope has isolated inputs.
Explore the guide Source-based guideSignal generator amplitude and the load setting
A generator’s displayed amplitude may be specified for a selected load. With a 50 Ω source set to 1 Vpp into 50 Ω, a high-impedance input can see almost 2 Vpp. The load menu usually changes the amplitude convention; it does not necessarily change the physical output resistance.
Explore the guide Source-based guideLCR readings need their measurement conditions
Capacitance, inductance and resistance readings depend on frequency, stimulus level, bias, equivalent-circuit model and the fixture. Compare LCR results only after matching those conditions. A single plausible number, especially in circuit, does not establish that a component is healthy.
Explore the guide Source-based guideNormal waveforms and fault-finding
A waveform is evidence about a circuit under stated conditions, not a verdict on a component. Define the expected signal, capture the operating state and test an alternative explanation. A reference trace is useful only when load, supply, timing and measurement setup are comparable.
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