Tektronix 3B2 TIME-BASE Instruction Manual page 8

4. Return the LEVEL control toward center until the trace
polarity; the display will reverse and start opposite to the
'
5. Connect another cable from the 5-voit calibrator jack
6. Repeat steps 3 and 4. Notice that the trigger controls
work the same as for internal trigger signals except the
trigger signals are used in certain applications, and these
are explained later in the text.
7. Adjust the trigger controls for a steady display. Set
to 1.00. Set the SWEEP DELAY switch to IN. The display
should move 2 divisions (10 msec} to the left.
The choice of triggering depends on the signal you
want to see. For example, if the display starts on the lead-
the SLOPE switch to the opposite position.
triggering, or with a higher bandpass vertical amplifier.)
The DC position must be used with signals that change
can be set to trigger the sweep a any voltage point on these
slow-rising signals.
For most applications, internal triggering will do. How-
2-2
to-point troubleshooting. With this method, the trigger
controls do not have to be adjusted for each point check.
Line triggering can be used for frequencies that are multiples
of the line frequency. An internal ac voltage (60 cps*) is
connected to the trigger circuit when the SOURCE switch
SWEEP CAL Adjustment
This front-panel screwdriver adjustment sets the gain of
the horizontal output amplifier. The gain should be checked
whenever the Type 3B2 is used with a different oscillo-
scope, since the deflection-plate sensitivity may not be the
fier plug-in unit is changed, since the power-supply loading
may be affected.
There are two methods for adjusting the gain of the hori-
zontal output amplifier. One uses the oscilloscope calibra-
tor signal (60 cps}; the other the digital readout unit.
Oscilloscope Calibrator Method
1. Set the Type 3B2 TIME/DIV switch to 5 mSEC.
2. Apply a 5-volt signal from the oscilloscope calibrator
to the Channel 1 input of the vertical amplifier.
3. Adjust the trigger controls on the Type 3B2 for a stable
nal across the 10 divisions of the graticule; if not, adjust
Digital Readout Method
1. Set the vertical amplifier input-coupling switch to
GND. Set the Type 3B2 TIME/DIV switch to 1 mSEC, and
adjust the trigger controls for a free-running sweep.
2. Set the digital unit controls as follows:
MODE TIME
TIMING START MANUAL
TIMING STOP MANUAL
RESOLUTION UNSCALED (MAX)
3. Adjust the TIMING START and TIMING STOP controls
on the digital unit for a readout of 0800.
4. Adjust the SWEEP CAL control on the Type 3B2 to
make the Start-to-Stop intensified zone of the display ex-
actly 8 horizontal divisions wide.
* Depends on line frequency.