Rear Panel - Keithley 148 Instruction Manual

OPERATION
MODEL 148 NANOVOLTKETER
d.
RANGE Switch.
The RANGE Switch selects the full-scale meter sensitivity
(either microvolts or millivolts) for one of nine ranges, from 0.01 to 100.
e. FUNCTION Switch.
The FUNCTION Switch selects the function - MICROVOLTS
or MILLIVOLTS - which is to be measured.
f.
ZERO SUPPRESS Controls.
Two controls determine the amount of zero suppression.
1.
The COARSE Control disconnects the suppression circuit (in OFF position)
or selects one of four suppression voltages in decade steps. Refer to Table 3.
2.
The FINE Control is a continuously variable adjustment for the suppression
voltage set by the COARSE Control. It adjusts the range between the positive
and negative values of the maximum voltage set by the COARSE Control.
g.
INPUT Receptacle.
The INPUT Receptacle is of a special low-thermal design.
Use only the Models 1481, 1482 and 1486 for mating connectors.
WER
5103:
RD
FIGURE 3. Model 148 Rear Panel Controls and Connections.
Circuit designations
refer to Replaceable Parts List and schematic diagrams.
2-2. REAR PANEL CONTROLS AND CONNECTIONS.
a. Line Voltage Switch. The screwdriver-operated slide switch sets the
Model 148 for 117 or 234~volt ac power lines.
b.
Fuse.
1.
For 117~volt operation,
use a 3 AG or MDL Slow-Blow l/8-ampere fuse.
2. For 234volt operation, use only a MDL Slow-Blow l/16-ampere fuse.
c.
Power Cord. The 3-wire power cord with the NEMA approved 3-prong plug
provides a ground connection for the cabinet. An adapter for operation from
2-terminal outlets is provided.
6
0464