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2-3-2. Single-trace Operation
Single-trace operation with single time base and internal triggering is the most
elementary operating mode of the Model 7040A. Use this mode when you wish to observe
only a single signal, and not be disturbed by other traces on the CRT. Since this
is fundamentally a two-channel instrument, you have a choice for your single chan
neL Channel has an output terminal ; use channel 1 if you also want to measure
frequency with a counter while observing the waveform. Channel 2 has a polarity
inverting switch. While this adds flexibility, it is not too useful in ordinary
single-trace operation.
The Model 7040A is set up for single-trace operation as follows
1. Set the following controls as indicated below. Note that the trigger source
selected (CHI or CH2 SOURCE) must match the single channel selected (CHI or
CH2 V MODE).
POWER switch (1)
ON (pushed in)
AC/GND/DC switches (11) (12)
AC
Vertical POSITION controls (19) (20)
Mid rotation and pushed in
VARIABLE controls (15) (16)
Fully CW and pushed in
V MODE switch (21)
CHI (CH2)
HORIZ DISPLAY switches (23)
A
A VARIABLE control (27)
Fully CW and pushed in
Trigger MODE switch (30)
AUTO
Trigger SOURCE switch (32)
CHI (CH2)
Trigger COUPLING switch (31)
AC
Trigger LEVEL control (34)
Mid rotation
HOLDOFF control (36)
NORM (fully CCW)
2. Use the corresponding Vertical POSITION control (19) or (20) to set the trace
near mid screen.
3. Connect the signal to be observed to the corresponding IN connector (9) or (10),
and adjust the corresponding VOLTS/DIV switch (13) or (14) so the displayed
signal is totally on screen.
CAUTION; Do not apply a signal
greater than 300 V (DC
+
peak AC)
4. Set the A TIME/DIV switch (24) so the desired number of signal cycles are
displayed. For some measurements just 2 or 3 cycles are best; for other
measurements 50-100 cycles appearing like a solid band works best. Adjust
the Trigger LEVEL control (34) if necessary for a stable display.
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