The probe is part of the measurement: its bandwidth must suit the scope, its attenuation (such as 1x or 10x) must match the scope’s setting, and it should be compensated before use. For mains or high-voltage circuits, the probe’s category and voltage rating and the scope maker’s instructions apply.
An oscilloscope is only as good as the probe feeding it.
Oscilloscope probe bandwidth
A probe has its own bandwidth rating. A probe rated below the scope limits the whole measurement. Probes supplied with a scope are usually matched to it, as the maker states.
Probe attenuation setting
1x passes the signal unchanged but loads the circuit more and has lower bandwidth. 10x divides the signal by ten, loads the circuit less and is the common default. The scope’s channel setting must match the probe switch.
Probe compensation
Each probe is compensated to its scope channel using the scope’s test signal, turning a small adjustment until square waves look square.
Probe grounding
The probe’s ground clip connects to the scope’s ground, which is often earthed through the mains plug. Connecting it to a point at a different potential creates a short. Scope makers explain safe grounding and differential measurement.
High-voltage measurements
Measuring mains or high-voltage circuits needs probes with the right category and voltage rating and the procedures the scope maker describes. Hobby benches rarely need it, and it is not a place to improvise.
Questions makers ask before buying
What does probe compensation do?
It adjusts the probe to the scope’s input so square waves display with flat tops rather than rounded or peaked edges. Scopes provide a test signal for it.
Why use 10x rather than 1x?
10x probes load the circuit less and usually have higher bandwidth, at the cost of reducing the signal by ten, which the scope compensates in its display.
Last reviewed 15 September 2026