Section III Model 122A/AR
Figure 3-15
CONNECTING EXTERNAL CAPACITORS TO EXTEND SWEEP TIME
:TO EXTERNAL -I
CAPACl TORS
AN-
- SIDE OF FRONTPANEL IN CABINET MODEL
RO
- TOP OF FRONT PANEL IN RACK-MOUNT MODEL
The slowest calibrated sweep provided on the Values of both capacitors are the same and
instrument is 1/5 second/cm. This can be ex- will be determined by the sweep speed desired.
tended with the SWEEP TIME VERNIER to at Note that the only ranges that these capacitors
least 1/2 second/cm or 5 seconds forthefull 10 will affect are the 50, 100, and 200 MICROSEC-
cm sweep. If you wish a slower sweep the range ONDS/CM ranges. The extension of the sweep
can be extended indefinitely by connecting a pair time is in proportion to the amount of capacity
of external capacitors to the sweep circuits. added to the circuit. Using 2 pfd capacitors will
increase the calibration of the above ranges to
approximately 0.5, 1, and 2 seconds/cm re-
To extend the sweep time, remove chassis from spectively.
cabinet.
The capacitor mentioned in step 1 of this figure
1. Connect external capacitor across capacitor must be a high-quality type such as mylar. No
shown on SWEEP TIME/CM switch. loss of sweep linearity occurs if a capacitor
with these specifications is used. The second
2. Connect external capacitor from point shown capacitor is connected to the hold-off circuits
to ground. and does not require special characteristics.
Figure 3- 15. Connecting External Capacitors to Extend Sweep Time
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ACEC
