Hameg HM2005-2 User Manual Download Page 30

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Subject to change without notice

C o n t r o l s a n d R e a d o u t

as X position control, i.e. it moves the signal display horizon-
tally.

The position control is especially useful when the magniﬁ er
(MAG x10

) is switched on. The magniﬁ er will magnify the

display 10 times around the screen centre, with the control the
portion of the signal to be studied can be shifted on-screen.

22.2

DELAY

If alternate A and B time base or B only time base mode is
present, the X POS DELAY pushbutton can be used to switch
over the function of the HORIZONTAL knob

from X position to

DELAY control. On condition DELAY is activated, the pushbutton
lights. Then the HORIZONTAL knob

can be used to determine

a delay time which must elapse before the B time base is star-
ted. The delay refers on the A time base start and is indicated
by the readout display “Dt:....”. If alternate time base mode (A
and B time base active) is present there is also an intensiﬁ ed
sector visible on the A time base trace. It`s start position (left)
also indicates the delay time. For further information please
refer to item

(HOR VAR pushbutton).

HORIZONTAL knob

The various functions of this knob depend on the operating mode
and are described under X-POS DELAY

pushbutton.

TIME/DIV.–VAR knob

This knob is normally used as the time base speed selector, but
has also other functions dependent on the operating mode. In
XY mode this control is disabled.

24.1

Time base A time/cm selection

This function is active if in the ”Time base“ menu (HOR VAR
pushbutton

) ”A only“ was selected and the option ”A variable

On Off“ was set to Off.

Turning the knob CCW will decrease, turning it CW will increa-
se the time base speed. The time base speed may be chosen

between 500 ms/cm... 50 ns/cm in a 1-2-5 sequence and will be
calibrated. The readout will show the setting (e.g. ”A:50ns“).

24.2

Time base B time/cm selection

This function is active if in the ”Time base“ menu (HOR VAR
pushbutton

) ”Search“ or ”B only“ was selected and the option

”B variable On Off“ was set to Off.

Turning the control CCW will decrease, turning it CW will in-
crease the time base speed. The speed can be selected between
20 ms/cm.. 50 ns/cm in a 1-2-5 sequence and will be calibrated.
The readout will show the speed (e.g. ”B:50ns“).

The time base B allows to display portions of the time base
A display on an expanded time base scale. This implies that
the speed of TB B must always be greater than that of TB A.
Therefore with the exception of 50 ns/cm TB B can not be set
to the same speed as TB A.

Further information is available in the section ”Time base B
(2

time base/Delay/Triggering“ in the chapter ”Triggering

and time bases“.

24.3

Variable

The TIME/DIV–VAR control may also be used to change the time
base speed continuously but uncalibrated. ”VAR“ will light up on
top of the HOR VAR pushbutton

in order to warn that the time

base is uncalibrated and the knob has now that function.

In order to arrive at that function press HOR VAR

which

calls the ”Time base“ menu. Depending whether time base
A or B is selected either ”A variable On Off“ or ”B variable On
Off“ will be shown. The function pushbutton can then be used
to select On/Off.

In order to point out that the time base is now uncalibrated
the readout will replace ”:“ by ”

“ preceding the time/cm. (e.g.

”A

500ns“ and ”B

200ns“). Also the results of cursor time/pe-

riod measurements will be marked that way.

VAR

x10

FOCUS
TRACE

VOLTS / DIV

VAR

VOLTS / DIV