The P6201 is an active (FET) probe providing unity gain and DC to 900 MHz bandwidth. The low input-capacitance of the probe permits coupling of high-frequency signals to an oscilloscope input with minimum loading on the circuit under test. Plug-on attenuator heads provide higher input resistance, reduced input capacitance, and attenuation of the signal. Effective DC offset range is also increased when using an attenuator head. The P6201 is designed primarily for use with TEKTRONIX 7000-Series, 475, or 485 Oscilloscopes, but may be used with 50-ohm sampling instruments and conventional oscilloscopes (with 1 ΜΩ input resistance). The internal 50-ohm termination may be switched in or out to adapt the probe output to either 1-megohm or 50-ohm inputs. The probe includes a locking-type BNC connector which provides scale-factor readout information to instruments having the readout capability. The 10X and 100X attenuator heads also couple readout information to the instrument via the output connector. The P6201 may be powered from the probe power output of the 7500, 7700, and 7900-Series Mainframes, the 475 and 485 Oscilloscopes, or by the 1101 Accessory Power Supply.