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2A61: Difference between revisions
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The Tektronix 2A61 is a differential amplifier plug-in for [[560-series scopes]]. | {{Plugin Sidebar 2 | | ||
title=Tektronix 2A61 | | |||
summary = Differential amplifier | | |||
image=Tek 2a61 front.jpg| | |||
caption=Tek 2A61 Front | | |||
series=[[560-series scopes]] | | |||
introduced=1963 | | |||
discontinued=(?) | | |||
manuals= | |||
* [http://bama.edebris.com/download/tek/2a61/2a61.djvu Tektronix 2A61 Manual (DjVu)] | |||
* [http://w140.com/2a61.pdf Tektronix 2A61 Manual (PDF)] | |||
}} | |||
The '''Tektronix 2A61''' is a differential amplifier plug-in for [[560-series scopes]]. | |||
It was [[introduced in 1963]]. | It was [[introduced in 1963]]. | ||
The deflection factor ranges from | |||
==Specifications== | |||
The deflection factor ranges from 10 μV/div to 20 mV/div. | |||
There are switch-selectable high-frequency and low-frequency cutoffs. | There are switch-selectable high-frequency and low-frequency cutoffs. | ||
At | |||
the maximum high-frequency cutoff is | At 20 mV/div, the minimum low-frequency cutoff is 0.06 Hz and | ||
is 50,000:1 at frequencies below | the maximum high-frequency cutoff is 300 kHz. | ||
10 | |||
The common mode rejection ratio is 50,000:1 at frequencies below 10 kHz. The input impedance at each input is 10 MΩ in parallel with 100 pF. The common mode range is +/- 5 V. | |||
The 2A61 has a line frequency filter that can be switched in our out of the signal path. | The 2A61 has a line frequency filter that can be switched in our out of the signal path. | ||
It is specified to attenuate line-frequency signal components by at least 50:1. | It is specified to attenuate line-frequency signal components by at least 50:1. | ||
==Internals== | |||
The front end consists of a differential amplifier. | The front end consists of a differential amplifier. | ||
| Line 18: | Line 37: | ||
Starting with serial number 987, the front-end differential amplifier | Starting with serial number 987, the front-end differential amplifier | ||
was made with four [[7586]] [[nuvistor]] triodes: V424, V425, V524, and V525. | was made with four [[7586]] [[nuvistor]] triodes: V424, V425, V524, and V525. | ||
The parallel combination of V424 and V425 forms one side of the differential amplifier | The parallel combination of V424 and V425 forms one side of the differential amplifier | ||
and the parallel combination of V524 and V525 forms the other side. | and the parallel combination of V524 and V525 forms the other side. | ||
However, for purposes of thermal stability, V424 is thermally connected to V524 | However, for purposes of thermal stability, V424 is thermally connected to V524 | ||
and V425 is thermally connected to V525. The tail current in the 987-and-up version is about | and V425 is thermally connected to V525. The tail current in the 987-and-up version is about 16 mA and the nuvistors have a plate-to-cathode voltage of about 70V. | ||
and the nuvistors have a plate-to-cathode voltage of about 70V. | |||
The second gain stage is a differential amplifier made of a pair of a pair of germanium PNP transistors. | The second gain stage is a differential amplifier made of a pair of a pair of germanium PNP transistors. To implement the low-frequency cutoff, | ||
To implement the low-frequency cutoff, | the 2A61 has a large electrolytic capacitor, | ||
the 2A61 has a large electrolytic | C437 (13,000 μF or 20,000 μF depending on serial number), | ||
C437 (13, | |||
in the emitter frequency compensation network | in the emitter frequency compensation network | ||
of the second differential amplifier stage. | of the second differential amplifier stage. | ||
Although C437 is polarized, it is operated with no DC bias | Although C437 is polarized, it is operated with no DC bias | ||
and therefore sees reverse voltage as part of normal operation. | and therefore sees reverse voltage as part of normal operation. | ||
| Line 39: | Line 58: | ||
Audio Generator. | Audio Generator. | ||
==Pictures== | |||
<gallery> | <gallery> | ||
File:Tek 2a61 front.jpg|Front | File:Tek 2a61 front.jpg|Front | ||
| Line 51: | Line 65: | ||
File:Tek 2a61 top.jpg|Top | File:Tek 2a61 top.jpg|Top | ||
File:Tek 2a61 bottom.jpg|Bottom | File:Tek 2a61 bottom.jpg|Bottom | ||
File:Tek 2a61 1.jpg | |||
File:Tek 2a61 2.jpg | |||
File:Tek 2a61 3.jpg | |||
File:Tek 2a61 4.jpg | |||
File:Tek-2a61 early.png|Schematic (early version) | File:Tek-2a61 early.png|Schematic (early version) | ||
File:Tek-2a61 late.png|Schematic (late version) | File:Tek-2a61 late.png|Schematic (late version) | ||
</gallery> | </gallery> | ||
[[Category:560 series plugins]] | |||