How Did The First Tv Work?

Do you remember, as a child, how you used to make a kind of primitive walkie talkie by running a string between two empty jam tins?

Well the first TV worked on the same principle but instead of jam tins they used mirrors.

(How on earth did you dig up this old question, Megan?)

You had to turn the knob before the remote.

Mechanically. John Logie-Baird had a rotating wheel with spirally located holes in it. According to the amount of light that made its way through the holes he transmitted more or less light to the receiver.