Amptec Research 620A SERIES, Руководство по эксплуатации и обслуживанию

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SECTION D: OPERATION AND USE
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D-1. General
This section contains complete operating
instructions for the AMPTEC 620A Series
Failsafe Ohmmeters. A description of the
front panel controls, connection instructions,
and the theory behind 4-wire resistance
measurement is discussed in this section.
D-2. Front Panel
» Power Switch
When the front panel power switch is placed
in the
OFF/CHARGE position, all power is
removed from the output terminals. While in
the “OFF” switch position, the battery pack
is connected to the rear panel charging jack
(see diagram next column).
When the front panel power switch is placed
in the
ON position, the battery pack is
disconnected (isolated) from the rear panel
charging jack. The possibility of a voltage
between the device under test and AC Power
ground is therefore eliminated. The operator
need not be concerned if the battery charging
adapter is plugged in while making
resistance measurements.
Range Switch
The AMPTEC 620A input range is selected
by depressing the desired button on a gold
plated multi-station interlocking pushbutton
array located on the right-hand side of the
front panel. The pushbutton for the lowest
resistance range is nearest to the POWER
switch.
D-3. Rear Panel
Fuseholder
The fuseholder is mounted on the rear panel
and contains a 2 amp in-line fuse. This fuse
is designed to protect the battery pack from
excessive charging currents. On some
620A versions a fuseholder is mounted on