Measurement loading is the change a measuring instrument causes in the circuit it observes. Instruments are not perfectly passive: for example, a voltmeter’s input resistance can draw a small current, while a current sensor may add resistance or other impedance. This can alter voltages, current flow, or signal shape, making the reading differ from the circuit’s undisturbed behavior.
In cybersecurity, this matters when engineers test hardware security features or analyze power and signal behavior. A probe can affect the device under test, potentially distorting measurements used to assess side-channel leakage or verify a defense. Attackers may also exploit circuit behavior through deliberate electrical interference, though that is distinct from ordinary measurement loading. Choosing suitable probes and sensors, accounting for their impedance, and comparing measurements with minimally intrusive methods help produce reliable results.