In this section:
Switch terminology ................................................................... 6-1
Switch terminology
The terms Form A, B, or C are used in switch terminology, throughout this manual, and are described
as follows:
•
Form A is simply a single-pole normally-open (SPNO) switch (see next figure) A double-pole
switch normally-open is classified as a 2 Form A.
•
Form B is similar to Form A except that its contacts are normally-closed (see next figure). A
double-pole switch normally-closed is classified as a 2 Form B.
•
Form C (see next figure) is a single-pole double-throw switch. It could also be a multiple switch
such as a double-pole which would be classified as a 2 Form C.
Figure 12: Switch terminology
Section 6
Switch terminology
