Power rail probes are designed to measure small AC characteristics of DC power rails. Due to their typical attenuation factor of 1:1, power rail probes add very little noise to the measurement. Some power rail probes include a built-in offset of up to ±60 V, to make maximum use of the oscilloscope vertical sensitivity (i.e. more bits of the oscilloscope’s ADC), resulting in a more accurate measurement with lower noise. In addition, the offset eliminates the need to use AC coupling or DC blocking caps, which impede the ability to see true DC values and drift. Power rail probes with bandwidths of up to 2 GHz and a slow rolloff help to capture high-frequency transients and coupled signals; the high input impedance (typically 50 kOhm) minimizes disturbance to measured rail signals