The machines today have been developed in the image and style of the original machine prototype but are totally computerized. Predetermined stopping points controlled by the computer chip are used to stop each reel, which in turn, are regulated by small, digitized bursts of electricity. The controlled bursts generated by the step motors are able to halt the spinning reels at exactly the right pre-appointed position.
This pre-programming that involves the payout percentage of a machine is determined by another device, called the Random Number Generator (RNG). Due to the RNG, each spin of the reels has an equal chance of striking a big win. With the RNG engaged, hundreds of numbers ranging from one to several billion are being generated each second. The number that is generated the exact millisecond a player presses the spin button or pulls the slot arm is the same number that will then be processed into a program that syncs the number with where the particular stopping point will be for each reel.
The operations of a 3-reel slot machine
When you pull the handle or press the button, the computer records the next three numbers from the RNG. The first number is used to determine the position of the first reel, the second number for the second reel and the third number for the third reel.
For this example, let’s say the first number is 123,456,789.
The player begins by pushing the spin button or pulling the handle of the machine, at which time the computer chip will record the very next three numbers that were generated by the RNG. Each number corresponds to one of the reels (3 numbers for 3 reels), which are then processed into a simple calculation that will finally create a number that tells the reels where to stop. Let us say the first number corresponding to the first reel is 333.
The calculation that is used next involves dividing the RNG generated number by multiplied values of 32, up to a value of 512. Since each machine is programmed differently, for the above example we shall say the computer chip uses the value of 32.
After running this particular calculation, we get 14 with a remainder of 2. The remainder is an important consideration for it shows there are only 32 possible end results of this calculation (it cannot be larger than 32 or smaller than 0). The computer then maps the 32 possible values out as stops on a computerized reel of 32 stops.
These computerized stops each correspond to the actual stops on the reel (they tell the reels which stop to cease spinning). Since there are less actual stops on a reel than the 32 stops on the computerized reel, some of the actual stops will correspond to more than one of the computerized stops. And when you add all three reels together, the possibilities are exponential.
This mode of operation is a great advantage to modern day slot machines. The computer system is responsible for governing whether a machine is going to be loose or tight, and just how much money it pays out over the long run. The supervision is minimized and you get mathematically accurate result.