Example of a remote locking device

 
This model of a remote locking device uses two electromagnets to lock and unlock the gate.

   
Notice how the switches are made from simple paper clips held in place with drawing pins.
   

The lock is sturdy when locked.

Click to see how it works. Notice how two electromagnets control the locking device.

Notice how the light must be on before the gate can be closed. Is this a series or parallel circuit? Explain.

What else in the video is indicative of the type of circuit you identified above?