How VCRs Work

By: Marshall Brain  | 

Components of the VHS Tape

A VHS tape is pretty intricate device in its own right, and it's a classic miracle of mass production.

If you take a video tape apart, you will find that it contains:


  • the top and bottom pieces of the outer shell
  • a moving, spring-loaded door to protect the tape
  • two spools to hold the tape
  • an 800-foot (244-m) long, 1/2-inch (1.3-cm) wide piece of oxide-coated Mylar tape that acts as the recording medium
  • several low-friction rollers to guide the tape across the front of the shell
  • two spring-loaded locks to prevent the tape from unrolling inside the cassette
  • Several screws to hold the whole thing together

­When the tape is inserted into a VCR, the VCR uses a lever to release and open the door, exposing the tape. It also inserts a pin into the hole to disengage the two locks on the spools. At that point, the drive can extract the tape and play it.