Mcclure
They are an SPDT switch, which mens they have the option of continuity on switch press (foward) and/or switch release (reverse).
The three terminals (usually) are:
C = Common
NC = Normally closed
NO = Normally open
You need to connect the C & NC for a forward switch. It is best to use a battery & bulb in a simple curcuit to test the correct connections for you.
You simply ignor the third terminal, it has no use for your application. I find the best configuration has the switch with the lever end pointing towards the tip of the pen. To fit the switch in some tapered pen bodies and keep the switch body flush with the pen body required me to snap of this terminal, it has no effect on the switch (just make sure you snap of the right one first!)
Benpaddlejones
