Z

The Tektronix Type Z is a comparator plug-in for 500-series scopes. Its two main subsystems are a differential amplifier and a precision variable DC voltage source, which can be used as one of the amplifier inputs. This allows DC-coupled measurements of small signals with large DC offsets. Its maximum sensitivity is 50mV/div, and it achieves 40,000 to 1 common-mode rejection at DC and low frequencies. Its risetime as a general-purpose amplifier is 27ns (13MHz bandwidth), but it can track a common-mode risetime of 7ns.

The Type Z has two inputs, A and B, plus a precision comparison voltage, Vc, that is adjustable from 0 to +/-1V, 10V, or 100V via a ten-turn pot. It's possible to view A, -B, A-B, A-Vc, or Vc-B.

Unlike later comparators, it has a separate step attenuator for each input, permitting you to view the difference between signals of widely differing amplitudes. It is also the only comparator that can handle +/- 100V common mode at full sensitivity. The Type Z uses two turret attenuators.

With a pair of "Disconnect Signal" buttons, the Type Z was the first of the movement toward a "Gnd" position on the input switches.

The Type Z was introduced in 1960 and uses both tubes and transistors, capitalizing on the strengths of each. It was dropped after 1968.

The Type P6023 probe, introduced in 1962 with R and C compensation, was specifically designed for the Type Z but also marketed for the Type G.

• Tektronix Type Z Manual (BAMA)
• Tektronix Type Z Factory Calibration Procedure (PDF)

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  Front View

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  Left Side

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  Schematic

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  Attenuators