3B1
The Tektronix 3B1 is a time-base plug-in introduced in 1962 for 560-series scopes. It is compatible with all the members of the 560 scope family other than the 560 itself.
There is a switch that enables 5 × horizontal magnification, which makes the fastest sweep 100 ns/Div. The 3B1 has a delayed sweep and a regular sweep.
Key Specifications
| Trigger Frequency | DC to 10 MHz |
|---|---|
| Sweep Speeds | 1 Sec/div to 0.5 μs/div in 20 1-2-5 steps |
| Sweep Types | Normal and Delayed |
| Sweep Magnification | x5 |
Internals
The 3B1 uses vacuum tubes, bipolar junction transistors, and tunnel diodes.
The trigger input goes through the int/ext switch and then the AC/DC coupling switch, and then a 7895 cathode follower. The output of the cathode follower drives one base of a 2N2207 PNP differential amplifier which has a tunnel diode in the collector load. The tunnel diode generates pulses when it switches back and forth between its two stable voltages, which are capacitively coupled to a 2N2501 NPN common emitter amplifier.
The delay pickoff circuit is a 6DJ8 differential amplifier that compares the sweep ramp voltage with a knob-controlled DC voltage which determines the point where the delayed trigger starts. The DC voltage is made by a ZZ1000 80 V reference passed through a potentiometer-variable voltage divider.
When the sweep ramp exceeds the control voltage, a 2.2 mA tunnel diode in the plate load of the differential amplifier switches state.
Pictures
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3B1 Front
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3B1 Left
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3B1 Right
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3B1 Bottom
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3B1 Top
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3B1 In 1965 Catalog
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3B1 Normal Trigger Circuit
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3B1 Delayed Trigger Circuit
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3B1 Delay Pickoff Circuit
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3B1 Normal Sweep Circuit
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3B1 Delayed Sweep Circuit
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3B1 Horizontal Amplifier Circuit
Some Parts Used in the 3B1
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 1N3714 | 152-0081-00 | Discrete component | 2.2 mA, 25 pF germanium tunnel diode | 546 • 547 • 556 • 21A • 22A • 3B1 • 3B2 • 3B3 • 422 • 491 • 283 |
| 2N2207 | 151-063 • 151-0063-00 | Discrete component | germanium PNP transistor | 321A • 3B1 • 3B3 • 547 |
| 6AL5 | 154-016 • 154-0016-00 • 154-0038-00 | Vacuum Tube (Dual Diode) | high-perveance dual diode | 163 • 181 • 190 • 1M1 • 310 • 310A • 315 • 316 • 317 • 3B1 • 3B1S • 3B2 • 3B3 • 3B5 • 502 • 502A • 503 • 511 • 511A • 512 • 516 • 517 • 517A • 524 • 526 • 535 • 535A • 545 • 545A • 549 • 551 • 565 • 570 • 581 • 581A • 585 • 585A • C • T • Telequipment S52 |
| 6BL8 | 154-0278-00 | Vacuum Tube (Triode/Pentode) | triode-pentode combo | 67 • 2B67 • 3B1 • 3B1S • 3B2 • 3B3 • 3B4 • 503 • 504 • 506 • 516 • 549 • 561 • 561A • 561S • 564 • 565 • 567 • Telequipment D52 • Telequipment S31 • Telequipment S32 • Telequipment S32A • Telequipment S51 • Telequipment S52 |
| 6DJ8 | 154-0187-00 • 154-0195-00 • 154-0305-00 • 154-0371-00 • 154-0413-00 | Vacuum Tube (Dual Triode) | dual triode | 132 • 161 • 310A • 316 • 317 • 502 • 502A • 503 • 504 • 506 • 515 • 516 • 519 • 526 • 529 • RM529 • 533 • 535 • 536 • 543 • 544 • 545 • 545A • 545B • 546 • 547 • 549 • 555 • 556 • 561A • 561S • 564 • 565 • 567 • 581 • 581A • 585 • 585A • 661 • 1A4 • 1S1 • 60 • 2A60 • 63 • 2A63 • 67 • 2B67 • 3A1 • 3A1S • 3A2 • 3A3 • 3A6 • 3A7 • 72 • 3A72 • 75 • 3A75 • 51 • 3B1 • 3B1S • 3B2 • 3B3 • 3B4 • 3M1 • 3S76 • 3T77 • 9A1 • 9A2 • 1121 • 80 • 81 • 82 • 86 • B • O • W • Z • Telequipment S32A • Telequipment D52 • Telequipment TD51 • Telequipment S52 • Telequipment S51 • Telequipment Type A • TU-4 |
| 7895 | 154-0378-00 | Vacuum Tube (Triode) | Nuvistor Triode | 3B1 • 3B1S • 3B3 |
| RT5204 | 151-0058-00 | Discrete component | Silicon NPN transistor | 565 • RM565 • Z • 2A61 • 3B1 • 3B3 • 3S76 • 3T77 |
| ZZ1000 | 154-370 • 154-0370-00 | Gas Discharge Tube (Voltage regulator) | 81 V voltage reference | 129 • 3B1 • 3B1S • 3B2 • 3B3 • 3S76 • 422 |