Wide bandwidth probes have a ____ Q factor and narrow bandwidth probes have a _____ Q factor.

• A. High; Low
• B. Low; High
• C. Medium; Medium
• D. Low; Low

Answer: (B)

Q factor measures how selective a circuit is around its resonant frequency. A high Q means the circuit stores energy well and responds only to a narrow range of frequencies, giving a very sharp, narrow bandwidth. A low Q means more energy is lost relative to stored energy, so the response is broader across frequencies.

For probes, a wide bandwidth requires the ability to operate over a broad range of frequencies, which comes with lower selectivity and thus a lower Q factor. Conversely, a narrow bandwidth probe is tuned to a tight frequency range and uses components with higher selectivity, resulting in a higher Q factor.

So wide bandwidth probes have a low Q factor, and narrow bandwidth probes have a high Q factor.