Jeulin JO 20 Manual page 21

Measurement and instrumentation
Dual trace oscilloscope JO 20 MHz
Ref :
291166
ENGLISH
(10) GAIN VARIATOR
This knob at the centre of the selector is used to attenuate the input signal
amplitude within a ratio of about 1 to 2.5.
The amplitude of the signal is measured when this knob is set on CAL.
(fully clockwise).
(11) Y POSITION
This knob controls the vertical displacement of the trace.
(12) X5 EXPANSION
The vertical axis gain is multiplied by 5.
(13) 3-POSITIONS LEVER:
Position 0: Channel input grounded, the probe is disconnected.
Position : Signal display via direct coupling (with the signal dc
component).
Position ~: Eliminates the dc component from the input signal.
(14) INV
This button is used to reverse the polarity of the YB signal (-YB).
In YA + YB mode, this yields YA - YB.
COMMON, CHANNELS A AND B:
(15) YA
This button is activated to confirm the display of the signal present on input
A.
(16) YB
This button is activated to select the display of the signal present on input
B.
(17) YA + YB
This button is used to sum the signals present on channels A and B.
Note: the activation of both the YA and YB buttons allows the simultaneous
display of the 2 signals.
(18) GROUND TERMINAL
Zone 3: HORIZONTAL (red)
(19) SECONDS/DIV.
Sweep rate selector.
(20) XY
The XY position eliminates the time component and allows the display of
YB relative to YA.
Beware of screen damage due to burning in the case of a bright
stationary spot.
(21) VARIABLE
This knob is used to fine-tune the sweep rate with a ratio of 1 to 2.5.
Time is measured when this knob is set on CAL (fully clockwise).
(22) X POSITION
This knob is used for the horizontal displacement of the trace.
(23) X 5 (X 10) EXPANSION (according to model)
This button is used to enlarge the trace 5 times (10 times) horizontally.
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