A slot is a slot machine, a type of gambling device that accepts cash or, in the case of ticket-in, ticket-out (TITO) machines, a paper ticket with a barcode. Once inserted, the machine activates a series of reels that rearrange symbols and award credits based on a paytable. The symbols vary by theme and style, but all slot games share a common element: a random number generator (RNG).
The RNG generates three random numbers every millisecond. Those numbers are then assigned to stops on the slot reels. The computer uses an internal sequence table to map those three numbers to a specific position on each reel. This is how the computer knows which stop to spin the next. The three numbers then become a sequence of symbols on the reels, and when the computer sees that sequence it triggers the appropriate action.
When a winning combination appears, the computer checks the paytable to determine how much to pay out. The payout is determined by the amount won divided by the amount wagered over a given time period. This is known as the RTP (return to player) rate.
It can be tempting to chase a slot that is supposedly due for a win, but remember that there is no such thing as a due slot payout. The result of each spin is determined by the RNG, and only those combinations that produce a winning combination will receive a payout.