In some ways, I understand photocells. You break the beam of light between them, it triggers something.
My question is the photo cells themselves. Here, I'm talking about garage door kinds. Is each a small transmitter and receiver?
Both seem to be powered up by the garage door opener. If one is a transmitter and one a receiver it would seem that it would require an expanded way of powering them.
Right now, there are two terminals. This sort of tells me each is a transmitter and receiver. Just curious.
My question is the photo cells themselves. Here, I'm talking about garage door kinds. Is each a small transmitter and receiver?
Both seem to be powered up by the garage door opener. If one is a transmitter and one a receiver it would seem that it would require an expanded way of powering them.
Right now, there are two terminals. This sort of tells me each is a transmitter and receiver. Just curious.