Overall
Block
Diagram
Figure
4-2
shows
the
overall
block
diagram
of
the
4339B .
Figure
4-2.
4339B
Overall
Block
Diagram
The
voltage
source
applies
dc
voltage
which
is
set
from
the
keyboard
or
by
an
GPIB
command.
The
I-V
converter
which
is
directly
connected
to
the
input
converts
the
current
owing
into
to
a
voltage
ramp
of
which
slope
is
proportional
to
the
input
current.
The
CPU
calculates
the
current
from
the
voltage
ramp
slope
,
then
calculates
the
DUT
resistance
by
dividing
the
source
voltage
by
the
current.
4-4
T
roubleshooting
