Voltage Measurement - Goldstar OS-7020 Service Manual

6-2 Voltage measurement
6-2-1 DC Voltage Measurement
1. Set the AC-GND-DC switch to GND. The vertical position
of the trace in this case is used as 0-volt reference
line as shown in Fig. 6-2. Adjust the vertical position
control in order to place the trace exactly on a hori-
zontal graticule, which facilites the reading of sig-
nal voltage.
2. Set
the trigger MODE switch to AUTO.
Select a sweep rate so that the trace may not flicker.
3. Set the AC-GND-DC switch to DC, and apply the voltage
to be _measured to the input connector. The vertical
displacement of the trace gives the voltage amplitude
of the signal. When the trace shifts upward, the measur-
ed voltage is positive with regard to the ground poten-
tial when the trace shifts downward, the voltage is ne-
gative.
The voltage can be obtained by Equation(!) or (2).
a. Measurement with the xl position of the probe
\
Voltage(V)
=
VOLTS/DIV setting value(V/div)
x Displayed amplitude of input
signal(div) ------- (1)
b. Measurement with the Xl0 position of the probe
Voltage(V)
=
VOLTS/DIV setting value(V/div)
x Displayed amplitude of input
signal(div) xl0 -----(2)
!~--- t --t--r- - - - -t- -
;o~
Volt1ge is
~pplitd
t
I I I I I
l
I I I I I----''- - - o -
volt rlfererce
llnR
I
AC-CiND-DC
switch
to
CiND)
:i· ..
·1 · ..
r . +-+-
T I I I I I
l
•·•"-•••·I•••
•I•••••·••
I••••
Fig 6-2. DC Voltage measurement
12