[计] 乒乓开关; 触发器

[ noun ]
a hinged switch that can assume either of two positions
<noun.artifact>

Toggle switch \Tog"gle switch`\, n.
1. (Elec.) an electrical switch operated by pushing a lever
through a small angle of deflection. The lever has a
spring which returns it to its original position after the
pressure applied by the operator is released.
[PJC]

2. (Computer programming) A mechanism for acquiring input
from an operator, such that taking some action (such as
pressing a function key on a keyboard) will cause a
program variable to take a new value. The values are
usually changed in cyclic fashion, so that a certain
number of activations of the toggle returns the variable
to its initial value. When there are two values to the
variable, each activation of the toggle causes the
variable to assume the alternate value.
[PJC]