3-13
Figure 3-12.—Three-position locking switch.
Snap-Acting Switches
A SNAP-ACTING switch is a switch in which the movement of the switch mechanism (contacts) is
relatively independent of the activating mechanism movement. In other words, in a toggle switch, no
matter how fast or slow you move the toggle, the actual switching of the circuit takes place at a fixed
speed. The snap-acting switch is constructed by making the switch mechanism a leaf spring so that it
"snaps" between positions. A snap-acting switch will always be in one of the positions designed for that
switch. The switch cannot be "between" positions. A two-position, single-pole, double-throw, snap-acting
switch could not be left in an OFF position.
Accurate Snap-Acting Switches
An ACCURATE SNAP-ACTING SWITCH is a snap-acting switch in which the operating point is
pre-set and very accurately known. The operating point is the point at which the plunger causes the switch
to "switch." The accurate snap-acting switch is commonly called a MICROSWITCH. A microswitch is
shown in figure 3-13.
Figure 3-13.—Accurate snap-acting switch (microswitch).
The full description of the microswitch shown in figure 3-13 is a two-position, single-pole,
double-throw, single-break, momentary-contact, accurate, snap-acting switch. Notice the terminals
