Agilent Technologies U1401B, Руководство пользователя и сервисное руководство

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104 U1401B User’s and Service Guide
5 Application Examples
Junction Field-Effect Transistor (JFET) Switch Test
A JFET typically has three terminals, namely drain (D), gate
(G), and source (S). There are two types of JFET depending
on the channel type: p- channel and n- channel. It is
recommended that you obtain the specific data sheet from
the manufacturers. You can also use the U1401B to identify
a JFET by following the procedure below:
1
Turn the rotary switch to the position.
2
Connect the red and black test leads to the positive and
negative input terminals respectively. The positive
terminal will provide a positive test voltage.
3
In this example, we will use a JFET with TO- 92 package
as shown in
Figure 5- 10 .
4 Probe pin 1 with the red test lead, and pin 2 with the
black test lead. Then reverse the test leads and obtain the
reading. If both readings are <1 k
Ω
, you can assume that
these pins are the drain and source terminals. The
remaining pin 3 is the gate terminal. Always find out first
which pin is the gate terminal. Refer to
Table 5- 7 on
page 105.
Figure 5-10 TO-92 JFET
Most TO-92 JFET
will have pin 1 as
the drain.