Links
Industrial Products and Services: If you are looking for a device, a good place to start is the Thomas Register. Membership is required but free.
Basic electronics tutorials for three skill level
A free, well done tutorial on basic electronics
What is a Solenoid?
The basics of relays.
Custom Switches Inc. has many different kinds of switches
Stepper and DC motorized actuators
Information and technical forum on stepper motors
How does a stepper motor work?
Stepper motors from disk drives and How to use it
Links to Electrical safety topic