7A14: Difference between revisions

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(contribution per Tekscope Vol.11 No. 1 1979)
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|summary=120 MHz current probe amplifier
|summary=120 MHz current probe amplifier
|image=Tek 7a14 de.jpg
|image=Tek 7a14 de.jpg
|caption=7A14
|caption=Tektronix 7A14
|introduced=1969
|introduced=1969
|discontinued=1975
|discontinued=1975
|designers=Hans Springer;
|designers=Hans Springer;
|manuals=
|manuals=
* [[Media:070-0979-00.pdf|Tektronix 7A14 Manual]] (PDF)
* [[Media:070-0979-00.pdf|Tektronix 7A14 Manual]]
}}
}}
The '''Tektronix 7A14''' is a 120 MHz current probe amplifier vertical plug-in for [[7000-series scopes|7000 series]], intended to be used with passive current probes such as the [[P6021]] and [[P6022]].
The '''Tektronix 7A14''' is a 120 MHz current probe amplifier vertical plug-in for [[7000-series scopes|7000 series]], intended to be used with passive current probes such as the [[P6021]] and [[P6022]].
The 7A14 was designed by [[Hans Springer]].


The 7A14 is one of the original plug-in modules introduced at the start of the 7000 series in 1969.
The [[P6019]] and [[P6020]] also work but with reduced bandwidth flatness, and the [[P6019]] needs a [[131-0750-00]] adapter (s.b.)


In the 7A14, the ring around the input [[BNC connector]] that is used to identify ×10/×100 probes on voltage probes serves the purpose of detecting the difference between the P6021 and P6022 probes, and switching in appropriate gain and frequency compensation.
The 7A14 is one of the original plug-in modules [[introduced in 1969|introduced at the start of the 7000 series in 1969]].
The P6021 shorts this ring to ground, directly switching three relays connected to −15 V internally. When connecting a [[P6019]] probe, the ring must also be grounded but the probe connector does not have the matching pin.  The [[131-0750-00]] adapter solves this problem.
 
The front panel gain control screwdriver adjustment affects gain for either P6021 or P6022, i.e. swapping probes requires re-adjustment.


{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Deflection | 1 mA/Div to 1 A/Div in 1–2–5 sequence }}
{{Spec | Deflection | 1 mA/Div to 1 A/Div in 1–2–5 sequence }}
{{Spec | Bandwidth | P6021: 25 Hz – 50 MHz (55 MHz in [[7904|79xx]])<br />
{{Spec | Bandwidth | P6021: 25 Hz – 50 MHz (55 MHz in [[7904|79xx]])<br />P6022: 250 Hz – 105 MHz (120 MHz in [[7904|79xx]], 80 MHz in [[7603|76xx]])}}
P6022: 250 Hz – 105 MHz (120 MHz in [[7904|79xx]], 80 MHz in [[7603|76xx]])}}
{{Spec | Features | Bandwidth limiting switch (20 MHz), polarity switch}}
{{EndSpecs}}
{{EndSpecs}}
==Operation==
In the 7A14, the ring around the input [[BNC connector]] that is used to identify ×10/×100 probes on voltage probes serves the purpose of detecting the difference between the [[P6021]] and [[P6022]] probes, and switching in appropriate gain and frequency compensation.
The [[P6021]] shorts this ring to ground, directly switching three relays connected to −15 V internally. When connecting a [[P6019]] probe, the ring must also be grounded but the probe connector does not have the matching pin.  The [[131-0750-00]] adapter solves this problem.
The front panel gain and low frequency compensation screwdriver adjustments do not differentiate between the [[P6021]] or [[P6022]] probes, i.e. swapping probes requires re-adjustment. Note that the low frequency compensation adjustment has a large impact on waveform accuracy and requires careful adjustment to a certain slope when using a 1 kHz calibrator signal as discussed in the manual.


==Links==
==Links==
* [http://www.barrytech.com/tektronix/tek7000/tek7a14.html Tek 7A14 @ barrytech.com]
* [http://www.barrytech.com/tektronix/tek7000/tek7a14.html Tek 7A14 @ barrytech.com]
{{Documents|Link=7A14}}


==Internals==
==Internals==
The 7A14 uses twelve Tek-made [[miniature relays]] that can be a service issue.
The 7A14 uses twelve Tek-made [[miniature relays]] that can be a service issue.


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|-
|-
! Catalog price
! Catalog price
|width=4em align=right|  $575
|width="4em" "align="right" |  $575
|width=4em align=right|  $700
|width="4em" align="right"  |  $700
|-
|-
! 2021 value
! In 2023 Dollars
|align=right| $4,260
|align="right" | $4,800
|align=right| $3,860
|align="right" | $4,400
|-
|-
|}
|}


==Pictures==
==Pictures==
<gallery>
<gallery>
Tek 7a14 1.jpg
Tek 7a14 1.jpg
Line 69: Line 71:
</gallery>
</gallery>


==Measurement examples==
Current through a 50 Ω resistor measured with [[P6021]] (top trace) compared to the voltage across the resistor (bottom trace). Measured with [[7854]] and [[7A26]] illustrating the low frequency limitation of the different probe termination methods. In the 10 mA/mV setting of the termination box the gain of the scope's vertical amplifier is insufficient to scale the current trace to the same nominal size as the voltage trace. <br />
The signal shown is a squarewave from a [[PG501]] @ 4 V<sub>p-p</sub> into 50 Ω = 80 mA<sub>p-p</sub>.
====5 kHz Squarewave====
<gallery>
P2021_7A14_5kHz.jpg | [[P6021]]+7A14
P2021 pass 2mApermV 5kHz.jpg  | [[P6021]]+passive termination 2 mA/mV
P2021 pass 10mApermV 5kHz.jpg  | [[P6021]]+passive termination 10 mA/mV
</gallery>
====500 Hz Squarewave====
<gallery>
P2021_7A14_500Hz.jpg | [[P6021]]+7A14
P2021 pass 2mApermV 500Hz.jpg  | [[P6021]]+passive termination 2 mA/mV
P2021 pass 10mApermV 500Hz.jpg  | [[P6021]]+passive termination 10 mA/mV
</gallery>
====50 Hz Squarewave====
<gallery>
P2021_7A14_50Hz.jpg | [[P6021]]+7A14
P2021 pass 2mApermV 50Hz.jpg  | [[P6021]]+passive termination 2 mA/mV
P2021 pass 10mApermV 50Hz.jpg  | [[P6021]]+passive termination 10 mA/mV
</gallery>
==Components==
{{Parts|7A14}}


[[Category:7000 series vertical plugins]]
[[Category:7000 series vertical plugins]]

Latest revision as of 14:58, 18 August 2024

Tektronix 7A14
120 MHz current probe amplifier
Tektronix 7A14

Compatible with 7000-series scopes

Produced from 1969 to 1975

Manuals
(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix 7A14 is a 120 MHz current probe amplifier vertical plug-in for 7000 series, intended to be used with passive current probes such as the P6021 and P6022. The 7A14 was designed by Hans Springer.

The P6019 and P6020 also work but with reduced bandwidth flatness, and the P6019 needs a 131-0750-00 adapter (s.b.)

The 7A14 is one of the original plug-in modules introduced at the start of the 7000 series in 1969.

Key Specifications

Deflection 1 mA/Div to 1 A/Div in 1–2–5 sequence
Bandwidth P6021: 25 Hz – 50 MHz (55 MHz in 79xx)
P6022: 250 Hz – 105 MHz (120 MHz in 79xx, 80 MHz in 76xx)
Features Bandwidth limiting switch (20 MHz), polarity switch

Operation

In the 7A14, the ring around the input BNC connector that is used to identify ×10/×100 probes on voltage probes serves the purpose of detecting the difference between the P6021 and P6022 probes, and switching in appropriate gain and frequency compensation. The P6021 shorts this ring to ground, directly switching three relays connected to −15 V internally. When connecting a P6019 probe, the ring must also be grounded but the probe connector does not have the matching pin. The 131-0750-00 adapter solves this problem.

The front panel gain and low frequency compensation screwdriver adjustments do not differentiate between the P6021 or P6022 probes, i.e. swapping probes requires re-adjustment. Note that the low frequency compensation adjustment has a large impact on waveform accuracy and requires careful adjustment to a certain slope when using a 1 kHz calibrator signal as discussed in the manual.

Links

Documents Referencing 7A14

Document Class Title Authors Year Links
Tekscope 1969 V1 N5 Oct 1969.pdf Article Introducing the New Generation 1969 7000-series scopes • 7504 • 7704 • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7S11 • 7M11 • 7B50 • 7B51 • 7B70 • 7B71 • 7T11 • R5030 • 7000 series readout system • Miniature relays • Cam switches • Industrial Design • T7500 • T7700 • P6052 • P6053 • C-50 • C-51 • 204-2
Tekscope 1969 V1 N6 Dec 1969.pdf Article A New Logic for Oscilloscope Displays 1969 7000-series scopes • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7B50 • 7B51 • 7B70 • 7B71 • 7S11 • 7T11 • 7504 • 7704
7000 series brochure March 1973.pdf Brochure 7000 series brochure, March 1973 1973 7A11 • 7A12 • 7A13 • 7A14 • 7A15A • 7A16A • 7A17 • 7A18 • 7A19 • 7A21N • 7A22 • 7B50 • 7B53A • 7B70 • 7B71 • 7B92 • 7CT1N • 7D11 • 7D13 • 7D14 • 7D15 • 7M11 • 7L12 • 7S11 • 7S12 • 7T11 • 7704A • R7704 • 7904 • R7903 • 7603 • R7603 • 7403N • R7403N • 7313 • R7313 • 7613 • R7613 • 7623 • R7623 • P7001

Internals

The 7A14 uses twelve Tek-made miniature relays that can be a service issue.

The amplifier is an 8-stage discrete differential design. The plug-in contains no integrated circuits.

Prices

Year 1969 1974
Catalog price $575 $700
In 2023 Dollars $4,800 $4,400

Pictures

  • 7A14 front panel

    7A14 front panel

  • 7A14, left side

    7A14, left side

  • 7A14, right side

    7A14, right side

Measurement examples

Current through a 50 Ω resistor measured with P6021 (top trace) compared to the voltage across the resistor (bottom trace). Measured with 7854 and 7A26 illustrating the low frequency limitation of the different probe termination methods. In the 10 mA/mV setting of the termination box the gain of the scope's vertical amplifier is insufficient to scale the current trace to the same nominal size as the voltage trace.
The signal shown is a squarewave from a PG501 @ 4 Vp-p into 50 Ω = 80 mAp-p.

5 kHz Squarewave

  • P6021+7A14

    P6021+7A14

  • P6021+passive termination 2 mA/mV

    P6021+passive termination 2 mA/mV

  • P6021+passive termination 10 mA/mV

    P6021+passive termination 10 mA/mV

500 Hz Squarewave

  • P6021+7A14

    P6021+7A14

  • P6021+passive termination 2 mA/mV

    P6021+passive termination 2 mA/mV

  • P6021+passive termination 10 mA/mV

    P6021+passive termination 10 mA/mV

50 Hz Squarewave

  • P6021+7A14

    P6021+7A14

  • P6021+passive termination 2 mA/mV

    P6021+passive termination 2 mA/mV

  • P6021+passive termination 10 mA/mV

    P6021+passive termination 10 mA/mV

Components

Some Parts Used in the 7A14

Part Part Number(s) Class Description Used in
148-0034-00 148-0034-00 Discrete component miniature DPDT relay 5A48 • 7A11 • 7A13 • 7A14 • 7B70 • 7B71 • 7503 • 7904 • 7904A
148-0035-00 148-0035-00 Discrete component miniature SPDT relay 7A13 • 7A14 • 7B70 • 7B71
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