3A9: Difference between revisions

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|series=560-series scopes
|series=560-series scopes
|type=3A9  
|type=3A9  
|summary=1 MHz differential amplifier  
|summary=1 MHz differential amplifier plug-in
|image=Tek 3a9 front.jpeg
|image=Tek 3a9 front.jpeg
|caption=Tektronix 3A9 front  
|caption=Tektronix 3A9 front  
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Tek 3a9 preamp.png|Preamp (front-end) schematic
Tek 3a9 preamp.png|Preamp (front-end) schematic
</gallery>
</gallery>
==Components==
{{Parts|3A9}}


[[Category:560 series plugins]]
[[Category:560 series plugins]]
[[Category:Differential amplifiers]]
[[Category:Differential amplifiers]]

Latest revision as of 07:16, 28 November 2023

Tektronix 3A9
1 MHz differential amplifier plug-in
Tektronix 3A9 front

Compatible with 560-series scopes

Produced from 1969 to 1974

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

The Tektronix 3A9 is a differential amplifier plug-in introduced in 1969 for 560-series scopes. It shares similarities with the 3A10 transducer amplifier and the 7A22 from the 7000 series and 5A22N from the 5000-series scopes.

The 3A9 features a variable high-frequency cut-off from 100 Hz to 1 MHz and a variable low-frequency cut-off from DC to 10 kHz. When DC coupled, the 3A9 provides a variable offset voltage. The common mode rejection is 100,000:1.

Key Specifications

Bandwidth 1 MHz, LF limit switchable DC, 0.1 Hz to 10 kHz in ×10 steps, HF limit switchable 100 Hz to 1 MHz in ×3/×10 steps
Deflection 10 μV/Div to 10 V/Div in 1–2–5 sequence
Input impedance 1 MΩ // 47 pF (either input)
Signal ranges
Range Differential signal DC Offset Common mode
10 μV/Div to 10 mV/Div ±1 V ±1 V ±10 V
20 mV/Div to 0.1 V/Div ±10 V ±10 V ±100 V
0.2 V/Div to 1 V/Div ±100 V ±100 V ±500 V
2 V/Div to 10 V/Div ±1000 V ±1000 V ±500 V

Internals

The differential amplifier design is a variant of the 1A7A circuit, also used with modifications in the 3A10, 7A22, 5A22N oscilloscope plug ins, and 5030/5031 scopes. The AM502 and the 26A2 for the 2601 mainframe use BJTs for the offset current sources instead of JFETs. The 26A2 adds a common mode signal circuit which is connected to a LEMO probe connector.

The 3A9 provides differential high-impedance voltage inputs and an AC current probe input for use with 125-turn probes (P6021 or P6019).

The front-end of the 3A9 starts with a differential pair formed by the two N-channel JFETs in a 151-1027-00, Q133.

Pictures

Components

Some Parts Used in the 3A9

Part Part Number(s) Class Description Used in
151-0261-00 151-0261-00 Discrete component dual PNP transistor AM501 AM502 CG5001 CG551AP FG501 FG502 FG503 OF150 OF151 OF152 OF235 OS261 RM502A R1140 R5030 R5031 R7912 067-0679-00 067-0807-00 1101 1140A 1141 1142 1350 145 1450 1480 1481 1482 1485 1501 1801 1900 1910 1980 213 26A1 26A2 2620 285 3A9 3A10 3S1 3S2 3S5 3S6 432 434 4501 454 4601 4602 4610 4612 4620 4632 4634 4701 475 492 492A 492AP 494 494P 496 496P 5A13N 5A20N 5A21N 5A22N 5A26 5L4N 502A 5030 5031 576 690SR 7A22 7A29 7B51 7B71 7J20 7L5 7S11 7S12 7912AD
151-1027-00 151-1027-00 Discrete component dual N-channel JFET 5031 3A9 AM502