Reference
370B User Manual
3-55
Figure 3-32: CommonĆsource FET Configuration Family of Curves
Common Measurements for Field Effect Transistors.
gm (Static)
The static transconductance (source grounded) is I
D
/V
GS
. I
D
/V
GS
can be
measured with the Dot cursor. The I
D
/V
GS
of the device under test is
displayed in the beta OR gm/DIV readout.
gm (Small Signal)
The small-signal transconductance (source grounded) formula is DI
D
/DV
GS
.
To determine gm at various points in a family of curves, multiply the vertical
separation of two adjacent curves by the b OR gm/DIV readout or use the f
Line or Window cursor (refer to Collector Supply and Step Generator in the
FIRST TIME OPERATION portion of this section).
I
DSS
Drain-source current with zero V
GS
is measured from the common-source
family, with the CONFIGURATION set to BASE SHORT (EMITTER). It
should be measured above the knee of the curve.
Pinch-Off
Voltage Pinch-off voltage (V
p
) is measured by increasing the depression
voltage with the STEP GENERATOR OFFSET control and the STEP
AMPLITUDE control until the specified pinch-off current is reached by the
zero step.
BV
GSS
Gate-source breakdown voltage is measured with the drain shorted to the
source; place the gate lead of the device in the drain terminal of the test
socket, and the source lead in the gate terminal and the drain lead in the
source terminal. Set the CONFIGURATION to BASE SHORT (EMITTER)
To Next Page
Loading...
General