The brains of a slot machine are the random number generator. There are many misconceptions as to how the computer picks the numbers within a machine. One of the most common myths is that the slot machine is on a cycle which will let a player know when the machine is due to win. This is not realistic or even a possibility.
How it Works
A slot machine contains a microprocessor similar to those within a home computer. The processor runs a special program that generates numbers randomly which corresponds to the symbols found on the reel. Therefore the random number generator is in constant motion. As long as the machine remains powered, numbers are selected randomly every millisecond.
The program generates values between 0 and 4 billion which are then translated into specific numbers that correspond to a combination of symbols on the reels. The outcome of each spin is determined by the number chosen by the random number generator. This number is selected as soon as the spin button is pressed.
An algorithm is a series of instructions that generate the numbers. The accuracy of this algorithm is confirmed by the Casino Control Board in addition to other private agencies. They are insuring that the series of instructions is up to par with their standards and that the player is not being cheated by the house.
A Simple Example
Reel slot machines have a specific number of spaces that hold a symbol or a blank which are referred to as physical stops. Modern reels contain 22 physical stops. For instance, if there are 10 physical stops on a machine, the possible symbol combination is 1,000 (10 * 10 * 10). These combinations are known as the cycle. Therefore the odds of winning on a 3 reel machine are 1 in 1,000.
In theory, if a guest player 1,000 straight times, they would hit all combinations once. Obviously this is not usually the case. The more spins they play, the closer they reach the actual probability, similar to flipping a coin.
The random number generator is the mechanism that creates winners and losers as well as gives the house edge. All slot machines in casino contain a random number generator that makes the game fair. The mathematics of the algorithm is beyond the knowledge of basic gamblers, but is vital to the correct function of a slot machine.