Sencore PS163 User Manual

APPLICATIONS
AC VOLTAGE MEASUREMENT
The measurement of AC voltages is one of the more
important uses for an oscilloscope. The calibrated in-
puts of the PS163 make possible very accurate mea-
surements using the following procedure:
1. Use one of the 39G34 LO CAP PROBES to con-
nect the signal to be measured to either the CHANNEL
A or B input. If the amplitude of the voltage to be
measured is in doubt, start with the PPV PER DIV.
switch set to the 500 position. Set the INPUT
COUPLING switch to the AC COUPLED position.
2. Adjust the controls on the PS163 to display ap-
proximately two cycles of the signal, with an amp-
litude of at least one vertical division.
3. Use the 10 x10 grid to measure the vertical distance
between the points on the waveform that you wish to
measure. Be sure that the small center knob of the
PPV PER DIV switch is turned full clockwise. When
measuring small voltages, the width of the trace can be
a significant part of the total distance, so make all
measurements from the same side of the trace.
4. Multiply the distance measured by the setting of
the PPV PER DIV switch. The result is the voltage
between the two points measured. In the composite
video waveform shown in Fig. 2, the total distance
from the tip of the sync pulse to the most negative
point is 2.2 divisions. The setting of the PPV PER
DIV switch is 1 VOLT/DIV, so the total peak to peak
amplitude of the signal is 2.2VP-P. The distance from
the tip of the sync pulse to the blanking pedestal is
1 division so the amplitude of the sync pulse is 1V.
Fig. 2. Measuring peak-to-peak voltages.
DC VOLTAGE MEASUREMENT
The use of the DC coupled scope to measure both DC
as well as AC signals can speed servicing in many cir-
14
cuits, especially solid state. With the DC coupled
scope, servicing can be faster as you will not need to
keep switching back and forth between the scope and
the DC voltmeter. Here are two handy methods of
making DC voltage measurements with the PS163.
SINGLE TRACE METHOD
1. Set the VERTICAL INPUT to CHANNEL A and
the INPUT COUPLING switch to the center ground
position.
2. Use the CHANNEL A TRACE POSITION control
to center the trace on the major horizontal grid line
of the scope graticule.
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3. Set the coupling switch to DC and connect the
probe to the point where the signal is to be measured.
Start with PPV PER DIV. switch set to 500 VOLTS/
DIV and slowly turn the switch clockwise until the
trace moves up or down between three and four centi-
meters. An upward movement indicates a positive
voltage, a downward movement a negative voltage.
4. Note the number of centimeters or divisions the
trace has moved from the center graticule line and
multiply this by the setting of the vertical input
switch. If the trace moves up 4 divisions and the PPV
PER DIV. switch is set to 10 volts/Div., the volt-
age would be 10 volts/Div x 4 Div = +40 volts. NOTE:
CHANNEL B may also be used for DC voltage mea-
surements.
DUAL TRACE METHOD (Preferred)
Press the DUAL ALTERNATE VERTICAL INPUT
button, set the CHANNEL A PPV PER DIV. switch
so the expected voltage at the point to be measured
is less than 6 times the switch setting, set both the
CHANNEL A and B INPUT COUPLING switches to
the center ground position. Adjust the CHANNEL A
and B TRACE POSITION controls so both traces are
lined up with the major horizontal grid line. Connect
the CHANNEL A probe to the test point, and slide
the CHANNEL A INPUT COUPLING switch to the
DC Position. Count the number of divisions up or
down the CHANNEL A trace moves and multiply by
the setting of the PPV PER DIV. switch. If the
CHANNEL A trace moves down 3.4 divisions and the
PPV PER DIV. switch is set to .2 VOLTS/DIV., the
measured voltage is .2 VOLTS/DIV.x-3.4 Div = -.68
volts.

Sencore PS163 Specifications

General

Brand	Sencore
Model	PS163
Category	Test Equipment
Language	English