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Please be kind to this newb. I have been Googling and unable to find it. I remember in Physics class in HS (many many years ago) that we created circuits which were a switch that is closed by default, but rotates between open and closed at pre-determined rate when the switch is activated. Does any body have any clue what I am talking about here, or have I lost my mind? Thanks in advance.

Sounds like what you are asking for is a voltage controlled switch - or a relay - driven by a pulse generator.

The Pulse generator sets the frequency at which the switch toggles between on and off and the duty cycle sets the ratio between the on and the off interval.

Like this:

" ... switch that is closed by default, but rotates between open and closed at pre-determined rate when the switch is activated."

That description could also be for a rotary switch fitted on the output of a - suitably geared down - electric motor.

http://en.wikipedia.org/wiki/Stepping_switch

http://forum.allaboutcircuits.com/showthread.php?t=74358

Ring any bells?

:)

a DPDT relay and a capacitor the cap value sets your frequency, one set of poles swiches the relay coil the other controls a load