7A12: Difference between revisions
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{{Spec | Channel isolation | At least 3000:1 at 75 MHz }} | {{Spec | Channel isolation | At least 3000:1 at 75 MHz }} | ||
{{Spec | Maximum input | 350 V DC + Peak AC at 1 kHz or less}} | {{Spec | Maximum input | 350 V DC + Peak AC at 1 kHz or less}} | ||
{{Spec | Offset | {{Spec | DC Offset | At least ±500 divisions}} | ||
{{EndSpecs}} | {{EndSpecs}} | ||
Revision as of 09:05, 21 January 2022
The Tektronix 7A12 is a 120 MHz dual-trace vertical plug-in for 7000-series scopes. This original 7000-series plugin allows to compensate large dc offset voltages, however the offset voltage is not available on the front panel to be measured externally as with the 7A11.
Switches on the front panel control miniature relays in the signal path, such as those selecting input attenuators, through logic circuits. It uses the 155-0032-00 as a gain stage and the 155-0022-00 for channel switching.
The 7A12 was designed by Roy Hayes (who also designed the 3A3 and 3A8 before leaving for HP Loveland in Jan 1971). The Evaluation Engineer for the 7A12 was Peter Starič, co-author of the book "Wideband Amplifiers" with Erik Margan.
Key Specifications
| Bandwidth | 120 MHz (79xx) / 105 MHz (77xx) / 55 MHz (74xx) |
|---|---|
| Deflection | 5 mV/Div to 5 V/Div (1–2–5), variable up to 12.5 V/Div |
| Input impedance | 1 MΩ // 24 pF |
| Timing | Delay difference between channels < 500 ps |
| Channel isolation | At least 3000:1 at 75 MHz |
| Maximum input | 350 V DC + Peak AC at 1 kHz or less |
| DC Offset | At least ±500 divisions |
Links
Pictures
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Front view
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Front view
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Attenuator schematic with relays
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7A12 Amplifier PCB
Custom ICs used in the 7A12
| Page | Model | Part nos | Description | Designers | Used in |
|---|---|---|---|---|---|
| 155-0022-00 | M036 | 155-0022-00 • 155-0022-01 | analog multiplexer | Gene Andrews | 147 • 148 • 149 • 335 • 468 • 1430 • 1441 • 1461 • 1900 • 1910 • 2220 • 2221 • 2230 • 5223 • 5403 • 5440 • 5441 • 5443 • 5444 • 5A38 • 7313 • 7403N • 7503 • 7504 • 7514 • 7603 • AN/USM-281C • 7613 • 7623 • 7623A • 7633 • 7704 • R7704 • 7704A • 7834 • 7844 • 7854 • R7912 • 7912AD • 7912HB • 7904 • R7903 • 7904A • 7934 • 7A12 • 7A18 • 7A18A • 7A18N • 7B52 • 7B53N • 7D10 • 7D11 • 7D12 • NT-7000 • P7001 |
| 155-0032-00 | M55 | 155-0032-00 • 155-0032-01 | variable-gain transconductance amplifier (voltage in, current out) | Roy Hayes • Einar Traa | 335 • 464 • 465 • 465B • 466 • 475 • 475A • 475M • 634 • 650 • 651 • 652 • 653 • 655 • 656 • 670 • 671 • 7A12 • 475 • FG504 • 1440 • 1460 • 1480 • 1481 • 1482 • 1485 |