19
Subject to change without notice
AUTOSET
For specifi c information consult ”Controls and Readout“ AU-
TOSET
11
.
The following description is valid for both analog and digital
modes. AUTOSET does not change from analog to digital mode
or vice versa. If in digital mode the modes ”Roll“, ”Envelope“
or ”Average“ (ACQUIRE) are present or the trigger mode
„Single“ (MODE) is selected, theses modes will be switched off as
AUTOSET always switches to ”Refresh“ acquistion. The signal to
be displayed must meet the amplitude and frequency require-
ments of automatic triggering, to enable a useful automatic
instrument setting.
All controls except for the POWER switch are electronically
scanned, all functions can also be controlled by the microcom-
puter, i.e. also via the interfaces.
This is a precondition for AUTOSET as this function must be able
to control all functions independent of control settings. AUTO-
SET will always switch to YT mode, but preserve the previous
selection of CH1, CH2 or dual trace; ADD or XY modes will be
switched to dual trace Yt.
Automatic setting of the vertical sensitivities and the time base
will present a display within 6 cm height (4 cm per signal in dual
trace) and about 2 signal periods. This is true for signals not
differing too much from a 1:1 duty cycle. For signals containing
several frequencies like video signals the display may be any.
Initiating the AUTOSET function will set the following operating
conditions:
– last selection of AC or DC coupling
− last selection of 1 M Ω or 50 Ω input impedance
– internal triggering
− automatic
triggering
− automatic trigger source selection
– trigger level set to the center of its range
– calibrated Y sensitivities
– calibrated time base
– AC or DC trigger coupling unmodified
– HF trigger coupling switched to DC
– LF or Noise Reject filters left
– X magnifier switched off
− Y and X positioning automatic
− trigger slope setting remains, except the slope setting is
“Both”
Please note:
For pulse signals with duty cycles approaching 400:1 no au-
tomatic signal display will be possible.
In such cases switch to normal trigger mode and set the trigger
position about 5 mm above the centre. If the trigger LED will
then light up a trigger is generated and the time base is opera-
ting. In order to obtain a visible display it may be necessary to
change the time base and V/DIV settings. Depending on the duty
cycle and the frequency the signal may still remain invisible.
This applies only to analog mode. In digital mode the trace is
always of equal brightness because not the signal is shown but
a low frequency construction of it, also, there is no information
in the trace intensity.
C o m p o n e n t T e s t e r
Component Tester
Specifi c information can be found in ”Controls and Readout“ un-
der COMPONENT/PROBE
40
and COMPONENT TESTER
41
.
The scope has a built-in component tester. The test object is
connected with 4 mm banana plugs. In this mode the Y amplifi ers
and the time base are turned off. Only individual components
may be tested, i.e. they must not be part of a circuit, if voltages
are to be applied to the BNC connectors. If the components
are part of a circuit this must be deenergized and disconnected
from safety ground. Except for the two test leads there may
be no further connection between scope and component. (See
”Tests within a circuit“). As described in section ”Safety“ all
ground connections of the scope are connected to safety ground
including those of the component tester. As long as individual
components are tested this is of no consequence.
The display can only be affected by the controls contained in
the FOCUS/TRACE menu: A-Int., Focus, Trace rotation, HORI-
ZONTAL position.
If components are to be tested which are parts of a circuit or
an instrument those circuits resp. instruments must fi rst be
deenergized. If they are connected to the mains they must be
unplugged. This will prevent a connection between scope and
circuit via the safety ground which may affect the measure-
ment.
STOP
Do not test charged capacitors.
The principle of the test is very simple: a sine wave generator
within the scope generates a 50 Hz ±10 % voltage which is
applied to a series connection of the test object and a resistor
within the scope. The sine wave proper defl ects in X direction,
the voltage across the resistor which is proportional to the test
current defl ects in Y direction.
If the object contains neither capacitors nor inductors, there will
be no phase shift between voltage and current, so a straight
line will show up which will be more or less slanted, depending
on the value of the object’s resistance, covering approx. 20 Ω to
4.7 kΩ. If there is a short the trace will be vertical, i.e. (almost)
no voltage produces already high current. A horizontal line will
thus indicate an open, there is only voltage but no current.
Capacitors or inductors will create ellipses. The impedance
may be calculated from the ellipse’s geometric dimensions.
Capacitors of appr. 0.1 μF to 1000 μF will be indicated.
– An ellipse with its longer axis horizontal indicates a high
impedance (low capacitance or high inductance)
– An ellipse with its longer axis vertical will indicate a low
impedance (high capacitance or low inductance)
– A slanted ellipse will indicate a lossy capacitor or induc-
tor.
Semiconductors will show their diode characteristics, however,
only 20 V
pp
are available, so the forward and reverse characte-
ristics can only be displayed up to 10 Vp in each direction. The
test is a two-terminal test, hence it is not possible to measure
e.g. the current gain of a transistor. One can only test B-C, B-E,
and C-E. The test current is only a few mA, so the test will not
harm ordinary semiconductors. (Sensitive devices like delicate
