21 (plug-in)
(Redirected from 21A)
The Tektronix Model 21 and successor 21A are time base plug-ins for the 555 dual-beam scope.
Type 21 is suggested as the upper beam time base, whereas sister model Type 22(A) is for the lower beam as it contains delayed trigger circuitry, and only the lower beam horizontal section is provided with delayed trigger pickup circuitry. The Delay multiplier control pot is also provided on the lower beam section.
Key Specifications
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Links
Pictures
Type 21
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21 front
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21 top
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21 bottom
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Type 21 and 22
Type 21A
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21A front
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21A top
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21 bottom
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21A TD trigger board
Components
Some Parts Used in the 21A
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 1N3714 | 152-0081-00 • 152-081 | Discrete component | 2.2 mA, 25 pF germanium tunnel diode | 067-0508-00 • 546 • 547 • 556 • 21A • 22A • 3B1 • 3B2 • 3B3 • 422 • 491 • 283 |
| 1N3717 | 152-0125-00 • 152-0125-01 • 152-125 • 152-0381-00 | Discrete component | 4.7 mA, 25 pF tunnel diode | 1L40 • 1S1 • 1S2 • 11B1 • 11B2 • 11B2A • 147A • 1470 • 148 • 21A • 22A • 3B4 • 3B5 • 408 • 432 • 434 • 453 • 453A • 454 • 466 • 491 • 5T3 • 544 • RM544 • 546 • RM546 • 547 • RM547 • 556 • RM556 • 7B70 • 7B71 • 7D11 |
| SMTD995 | 152-0140-01 | Discrete component | 10 mA, 8 pF tunnel diode | 1S1 • 1S2 • 1502 • 21A • 22A • 3T5 • 3T6 • 475 • 475A • 475M • 544 • R544 • 546 • RM546 • 547 • RM547 • 556 • R556 • 581A • 585A • RM585A • 7B52 • 7B53N • 7B70 • 7B71 • 7D10 • 7D11 • 7T11 • 7T11A • R7912 • S-51 • S-52 • TU-5 • 067-0572-00 • 067-0572-01 • 067-0681-00 |
| STD704 | 152-0125-00 | Discrete component | 4.7 mA tunnel diode | 1L40 • 1S1 • 11B1 • 11B2 • 11B2A • 147 • R147 • 147A • R147A • 1470 • 148 • R148 • 148-M • 149 • R149 • 149A • R149A • 21A • 22A • 3B4 • 3B5 • 408 • 432 • 434 • 453 • 453A • 454 • 464 • 465 • 466 • 491 • 5T3 • 544 • RM544 • 546 • RM546 • 547 • RM547 • 556 • RM556 • 7B70 • 7B71 • 7D11 |