Z
The Tektronix Type Z is a comparator plug-in for 500-series scopes, introduced in 1960 and dropped after 1968. It was designed by Charlie Rhodes and Ron Olson.
The Type Z has two inputs, A and B, plus a precision comparison voltage, VC, that is adjustable from 0 to ±1 V, 10 V, or 100 V via a ten-turn pot.
The following differential amplifier can be configured to display VA, −VB, VA−VB, VA−VC, or VC−VB.
This allows DC-coupled measurements of small signals with large DC offsets.
Unlike later comparators, Type Z has separate step attenuators for each input, permitting the user to view the difference between signals of widely differing amplitudes. Unfortunately the divider resistors have no trim, so CMRR is poor except at 50mV/div.
It is also the only comparator that can handle ±100 V common mode at full sensitivity.
With a pair of "Disconnect Signal" buttons, the Type Z was the first movement toward a "GND" position on the input switches.
The Type P6023 probe with R and C compensation, introduced in 1962, was specifically designed for the Type Z but also marketed for the Type G.
Key Specifications
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Maximum sensitivity is 50 mV/div, and common-mode rejection is 40,000:1 "from DC through audio frequencies".
Risetime as a general-purpose amplifier is 27 ns (13 MHz bandwidth). A side effect of Type Z's unprecedented dynamic range is that transient response is a function of signal amplitude: slew rates faster than 1 V in 6 ns will cause distortion due to grid current.
Links
Documents referencing Z
| Document | Class | Title | Authors | Year | Links |
|---|---|---|---|---|---|
| Service Scope 12 Feb 1962.pdf | Article | Measuring a Small AC Component Riding on a DC Voltage | 1962 | 502 • 503 • D • G • Z | |
| Tekscope 1972 V4 N5 Sep 1972.pdf | Article | A Practical Approach to Differential Amplifiers and Measurements (Part 1) | Fred Beckett | 1972 | 112 • 11A33 • 1A5 • 1A6 • 1A7 • 1A7A • 26A2 • 3A9 • 5A22N • 7A13 • 7A22 • AM502 • D • E • G • P6055 • P6046 • W • Z |
| Tekscope 1972 V4 N6 Nov 1972.pdf | Article | A Practical Approach to Differential Amplifiers and Measurements (Part 2) | Fred Beckett | 1972 | 112 • 11A33 • 1A5 • 1A6 • 1A7 • 1A7A • 26A2 • 3A9 • 5A22N • 7A13 • 7A22 • AM502 • D • E • G • P6055 • P6046 • W • Z |
Patents that may apply to Z
| Page | Title | Inventors | Filing date | Grant date | Links |
|---|---|---|---|---|---|
| Patent US 3074011A | Turret device for electric circuits | Langdon C Hedrick | 1958-10-20 | 1963-01-15 | H • 516 • 7A16 • Z • 1121 • Turret attenuators |
Prices
| Year | Catalog price | In 2026 dollars |
|---|---|---|
| 1962 | $525 | ~$5,700 |
Internals
The Type Z uses both tubes and transistors, capitalizing on the strengths of each.
The step attenuators are turret attenuators.
Pictures
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Front view
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3/4 View
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Front View
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Front View
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Pre-production Type Z with different knob color
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Left Side
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Left Side
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Right Side
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Right Side
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Right Side
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Right Side Tubes
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Top
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Rear
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Schematics
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Attenuators
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Main Amplifier
Components
Some Parts Used in the Z
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 0G3 | 154-0291-00 | Gas Discharge Tube (Voltage regulator) | 85 V voltage reference | 125 • 132 • 506 • 544 • 546 • 547 • 560 • 561 • 561A • 561S • 564 • 565 • 567 • 661 • TU-4 • Z • Keithley 610 • Keithley 660A |
| 12AT7 | 154-0039-00 | Vacuum Tube (Dual Triode) | dual high-gain triode | 161 • 180 • 310 • 310A • 315 • 316 • 360 • 502 • 502A • 511A • 512 • 513 • 513D • 514 • 514AD • 514D • 515 • 515A • 516 • 524 • 525 • 529 • RM529 • 544 • 546 • 547 • 556 • 565 • 570 • 3A2 • 75 • 3A75 • 1M1 • A • B • C • CA • G • H • K • L • ML • M • N • K • R • S • Z • Keithley 610B • Nelson-Ross PSA-021 • Pentrix L20 • Pentrix L30 |
| 12AU6 | 154-0040-00 | Vacuum Tube (Pentode) | RF pentode | 81 • 112 • 1L10 • 1L20 • 1L30 • 1L40 • 1L60 • 3L10 • 512 • 532 • 535A • RM35A • 544 • 546 • 545 • 547 • 549 • 556 • 575 • 581 • 585 • A • B • C • CA • G • K • H • L • ML • M • N • O • R • S • Z • Pentrix L20 • Pentrix L30 |
| 6AK5 | 154-0014-00 • 154-0206-00 • 154-0084-00 | Vacuum Tube (Pentode) | RF pentode | B • C • CA • G • K • L • ML • S • Z • 517 • 517A • 524 |
| 6DJ8 | 154-0187-00 • 154-0305-00 | Vacuum Tube (Dual Triode) | dual triode | 067-506 • 111 • 132 • 161 • 310A • 316 • 317 • 502 • 502A • 503 • 504 • 506 • 515 • 515A • 516 • 519 • 526 • 529 • RM529 • 531A • RM31A • 533 • 535 • 535A • RM35A • 536 • 543 • 544 • 545 • 545A • 545B • 546 • 547 • 549 • 555 • 556 • 561A • 561S • 564 • 565 • 567 • 581 • 581A • 585 • 585A • 661 • 1A2 • 1A4 • 1S1 • 60 • 2A60 • 63 • 2A63 • 67 • 2B67 • 3A1 • 3A1S • 3A2 • 3A3 • 3A6 • 3A7 • 72 • 3A72 • 75 • 3A75 • 4S2 • 51 • 3B1 • 3B1S • 3B2 • 3B3 • 3B4 • 3M1 • 3S76 • 3T77 • 3T77A • 9A1 • 9A2 • 1121 • 80 • 81 • 82 • 86 • B • O • Z • Telequipment D56 • Telequipment S32A • Telequipment D52 • S-311 • Telequipment TD51 • Telequipment S52 • Telequipment S51 • Telequipment Type A • TU-4 |
| RT5204 | 151-0058-00 | Discrete component | Silicon NPN transistor | 565 • RM565 • Z • 2A61 • 3B1 • 3B3 • 3S76 • 3T77 |