The 1123A Active Probe is used for probing high source impedances at high frequencies. The probe should be used to apply input signals to the 1802A 100MHz plug-in. This X1 active probe has very low drift and noise and provides an input RC of 100 kohms and only 3.5 pF. Bandwidth: DC to > 220MHz (3 dB down) Gain is adjustable to X1 into 50-ohm load Output of ? 0.5 V peak Maximum input of ? 50 V (DC + peak AC) Output impedance of 50-ohms