(a) Control Settings
(b) Result
Figure 8: N-Channel MOSFET
an internal impedance of 4k7
Ω
. (The DC impedance of a MOSFET gate is essentially infinite, so the internal
impedance of this voltage source is inconsequential.)
3.8
P-Channel MOSFET
For an P-Channel MOSFET, setup and operation of the curve tracer is similar to the N-Channel MOSFET, de-
scribed previously.
3.9
N-Channel JFET
The control panel settings and a typical result are shown in figure 10.
For the JFET, the value of Idss (drain current with zero gate-source voltage) is often of interest. This can
be obtain from the VI plot. However, to eliminate any possible voltage between gate and source, it’s useful to
connect only the source and drain terminals to the curve tracer, as in figure 10. The gate terminal is connected to
the source terminal of the JFET, and not connected to the curve tracer. Now the characteristic curve will show the
drain voltage-current characteristic with zero Vgs.
11
