|50 ns/div to 5 s/div|
|X50 Direct Reading Magnifier|
|Triggering to 20 MHz|
|Single Sweep Operation|
|Calibrated External Horizontal Input|
|Net Weight - 5 lb|
|Tunnel Diode Trigger Circuit||
The Type 3B4 Time Base Plug-in unit is designed to be used primarily with the Tektronix Type 561A Oscilloscope
system; however, it can also be used with the other 560-Series systems that use 3B-Series plug-in units such as
the Type 564 and Type 567. As part of an oscilloscope system, the Type 3B4 is used as an accurate time base
generator or as a calibrated amplifier for externally generated deflection signals.
The Type 3B4 provides calibrated sweep rates from 0.05 μsec/div to 5 sec/div in 25 calibrated steps. A
five-step, direct-reading magnification feature provides magnification up to 40 X or 50 X, depending on the
sweep rate to which magnification is applied. When the Type 3B4 is used as an amplifier for externally generated
deflection signals, the magnifier provides five steps of deflection sensitivity, from 0.2 volts/div to
5 volts/div. In addition, a variable control provides uncalibrated sweep rates and deflection sensitivities
between the calibrated steps. By using the variable control, uncalibrated sweep rates from 0.05 μsec/div to
approximately 12.5 sec/div and deflection sensitivities from 0.2 volts/div to approximately 12.5 volts/div
are available. Uncalibrated operation is indicated by a neon lamp.
|TIME/DIV Switch|| ||0.2 μsec/div to 5 sec/div in 23 steps, 1, 2, 5 sequence.
The calibration accuracy (unmagnified) is ±3% from 0.2 μsec/div to 2 sec/div; ±5% at
|MAGNIFIER Control|| ||Provides direct readout magnification of the sweep (up to 50 X).
The magnifier also provides the 0.05 and 0.1 μsec/div sweep rates. Magnified sweep accuracy, ±5%
(exception: 5 sec/div). Magnified sweep registration, ±1 minor division.|
|TRIGGER MODE Switch|| ||Free Run, Auto, Normal, and Single Sweep|
|SLOPE Switch|| ||+ or -|
|COUPLING Switch|| ||Ac, Ac Low-Frequency Reject, and Dc|
|SOURCE Switch|| ||Internal, Line, External, and External ÷ 10|
TRIGGERING LEVEL Control Voltage Range (external triggering)
|EXT||AC, DC or|| || |
|AC LF REJ||± 19 v||± 15 v|
|EXT ÷ 10||AC, DC or||± 190 v|| |
|AC LF REJ|| ||± 150 v|
|AC||AC LF REJ||DC|
|INT||1 minor division of deflection 30 Hz to 20 MHz. Outside these limits requires larger triggering signal.
||1 minor division of deflection 30 kHz to 20 MHz. Outside these limits requires larger triggering signal.
||1 minor division of deflection dc to 20 MHz (with trace vertically centered). Above 20 MHz requires larger triggering signal.|
|EXT||0.2v 30 Hz to 20 MHz. Outside these limits requires larger triggering signal.
||0.2v 30 kHz to 20 MHz. Outside these limits requires larger triggering signal.
||0.2v dc to 20 MHz (with trace vertically centered). Above 20 MHz requires larger triggering signal.|
EXTERNAL HORIZONTAL INPUT
0.2 V/div to 5 V/div in 5 calibrated steps (max input ±20V); accuracy, when plug-in unit is matched to oscilloscope, is within 3%. The External Input Amplifier is DC coupled.
(excerpt from Tektronix® Instruction Manual)
The following control and switch settings for the Type 3B4 can be used for a wide range of measurements.
The operating conditions established by these settings also provide a starting point for the operator who
is learning to use the instrument.
|VARIABLE (TIME/DIV)||CALIB (fully clockwise)|
|MAGNIFIER||Locked to TIME/DIV switch|
The Type 3B4 now provides the time base for measurements of vertical deflection signals above about 20 Hz.
In many cases, only the TIME/DIV switch and the TRIGGERING LEVEL control require readjustment when progressing
from one measurement to the next.
TIME/DIV OR HORIZONTAL VOLTS/DIV
The Time Base has 23 calibrated sweep rates ranging from 0.2 μsec/div to 5 sec/div (unmagnified). The
number opposite the dot on the MAGNIFIER knob indicates the sweep time per division as long as the VARIABLE
control is in the CALIB position. The unmagnified sweep rate value being used appears between the two
black lines on the clear plastic flange of the TIME/DIV control. The CARIABLE control and MAGNIFIER switch,
used in conjunction with the TIME/DIV switch, permit the sweep rate to be varied continuously between
50 nsec/div and about 12.5 sec/div.
When the flange is positioned so that the two heavy black lines bracket the EXT HORIZ IN position the
horizontal amplifier input is connected to the EXT HORIZ IN connector and accepts external horizontal
deflection signals. In this mode of operation, five ranges of horizontal deflection sensitivity are available.
The five sensitivity ranges are from 0.2 volts/div to 5 volts/div.
To position the TIME/DIV switch to the EXT HORIZ IN position, turn the MAGNIFIER knob until the dot on the
knob is positioned between the two black lines on the clear plastic flange. Turn the knob until the two black
lines on the flange bracket the position marked "EXT HORIZ IN". The external horizontal deflection sensitivity
may now be selected by pulling the MAGNIFIER knob outward to unlock it, then, while holding the knob out, turn
it to the desired volt/div position.
The sweep ranges between 5 sec/div and 2 μsec/div can be magnified up to 40X or 50X in 5 steps. The
degree of magnification is the ratio between the indicated magnified rate (number opposite the dot on the
skirt of the MAGNIFIED knob) and the indicated unmagnified rate (number bracketed by two black lines on the
clear plastic flange). Since the magnified display rate is always direct reading, it is seldom necessary to
determine the actual magnifying factor used.
(excerpt from Tektronix® Instruction Manual)
|331-132||Dial, window knob for TIME/DIV|
|366-038||Knob, small red, VARIABLE|
|366-138||Knob, charcoal, POSITION|
|366-173||Knob, charcoal, TRIGGER MODE|
|366-173||Knob, charcoal, TRIGGERING LEVEL|
|366-215||Knob for 3-lever switches|
|366-255||Knob, small red, FINE Position|
|366-269||Knob, large charcoal, TIME/CM|
|R16||311-217||2 x 1 Meg Var TRIGGERING LEVEL|
|R229||311-481||20K and 30K dual pot w/ SW229 VARIABLE|
|R402||311-315||20K pot SWEEP CAL|
|R406/R409||311-478||150K / 1 meg dual pot POSITION|
|SW10||260-472||Switch, lever, SLOPE|
|SW130||260-263||Sw, rotary TRIGGER MODE|
|SW135||260-518||Switch, push-pull w/ red light, MAGNIFIER|
|SW160||260-624||Sw, rotary, TIME/DIV|
|SW5||260-615||Switch, lever, SOURCE|
|SW8||260-594||Switch, lever, COUPLING|