Tektronix 323, Instruction Manual

Page: 28 / 170

Operating Instructions— Type 3 2 3
INPUT DC
VOLTS/DIV .02
VARIABLE (VOLTS/DIV) CAL
TIME/DIV .5 ms
X 10 VERT GAIN In
X 10 HORIZ MAG In
TRIGGER + AUTO
Trig/Horiz Coupling INT TRIG-AC
(b) Connect the P6049 Probe BNC connector to the VERT
INPUT connector.
(c) Connect the P6049 Probe tip to the .5 V CAL OUT
jack (left side of oscilloscope).
d) Check the waveform presentation against Fig. 2-10(A).
Waveform presentations resulting from incorrect adjustments
are shown in Fig. 2-10(B) and (C).
(e) The probe adjustment is contained in the compensa­
tion housing which connects to the Oscilloscope INPUT con­
nector.
I A ) Correct
(C l Incorrect
Fig. 2 -1 0 . Probe com pensation.
Using a screwdriver, adjust it as necessary to obtain op­
timum square leading corners on the square wave presen­
tation. Rounding or overshoot should be minimized.
MISCELLANEOUS OPERATING HINTS
WARNING
Failure to complete the ground circuit o f the Type
323 w ill cause the entire unit to be elevated to
the voltage o f the applied signal.
Reference or ground lead. Reliable signal observations
cannot be made unless both the oscilloscope and the unit
under test are connected together by a reference (ground)
lead in addition to the signal lead. See Fig. 2-11. Most
AC-operated equipment has a common ground supplied
by the AC power source circuitry. This is true of the Type
323 Oscilloscope whenever the 3-wire AC line cord is con­
nected to the oscilloscope and a grounded AC source. Dur­
ing internal battery or external DC operation, a reference
(ground) lead must be externally connected between the
oscilloscope and the equipment under test.
n
r ~
r ----- —
n
i
m i
L
■ i i
. . .
]
—
(A ) G round loop not com pleted.
St
■v:
. Y-i ■
')
(B) G round loop com pleted.
Fig. 2 -1 1 . G round loop effect.
Ringing. It is not uncommon to have ringing accompany
a waveform presentation. It usually results from inductance
associated with the reference or signal leads. If the AC
supply common (ground) is used as the reference lead, the
length of wire involved introduces considerable inductance.
To reduce inductance and the resultant ringing, use the
2-16
® I