Random Number Generator

Computer chip inside a slot machine which constantly generates random number sequences.

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When a player hits spin on a slot machine, the chip chooses a random number, which determines the outcome of the spin.

Each possible combination of reel symbols has a number which corresponds to it. The Random Number Generator chip produces a random number and the slot machine's computer compares that number against the reel symbol combinations. The slot machine then displays the appropriate reel symbol combination and gives coins or credits when the combination is a winning one.

RNGs produce hundreds and hundreds of random numbers per second and uses only the most recent when a player hits the spin button, so if a player hit the button a fraction of a second earlier, that player would have received a different reel combination. The slot machine lever and the reels are these days a part of the slot machine purely for the sake of entertainment or convention, because players have come to expect those features on a slot machine.

Random number generators first appeared in slot machines in the 1970's, but didn't begin to change the slots industry until the 1980's. RNGs offer many options not available in the mechanical era of slot machines. With random number generators, slot machines would not be able to feature progressive jackpots.