Components That Make Slot Machines Tick

Random Number Generators in Slots

The RNG is at the heart of a video slot, ensuring that each spin has an equal chance of producing a winning combination. The RNG can generate hundreds of random numbers each second and relies on complex algorithms to do so. It is always working, even when no one is playing the machine.

As long as the slot is plugged in, the RNG continuously produces random whole numbers, usually between 1 and a couple of billion. The computer records the numbers generated at the exact millisecond the player hits the spin button and feeds them into a program that decides where the virtual reels must stop.

All combinations are equally possible on each spin because the RNG uses a full set of numbers every round. A random number is selected and mapped onto each of the spinning reels, telling the game at which position they must stop. The reels are set into motion to build suspense, but this is just for show. The outcome of the round is predetermined the moment the player hits the spin button.

The way the symbols are mapped on the virtual reel is game-specific. In some of the more advanced games, pressing the Bet One button, the Maximum Bet button, or pushing the lever causes the algorithm to start at different points.

The use of computer chips has revolutionized slot machines, giving manufacturers and players alike more flexibility. You can now use bills to purchase a predetermined amount of credits instead of feeding coins into the machine on every spin. Additionally, both players and gambling operators can easily track how much is won or lost on a given machine.

The Virtual Reels

Modern slots use virtual reels, which allow for a much larger number of possible symbol combinations than those in games with physical reels. After all, mechanical reels must fit inside the slot’s casing, and adding more symbols per reel is possible only up to a certain point.

Casinos need more symbol combinations than mechanical reels can offer if they want to provide slots with odds capable of producing huge jackpots. To achieve this, symbols and spaces are mapped on virtual reels, which significantly increases the number of potential combinations.

Suppose you have a slot with a physical reel that has 10 spaces and 10 symbols – for example, 1 lucky seven, 2 plums, 3 lemons, and 4 cherries. Depending on the manufacturer, each identical symbol can be assigned an equal or a different number of stops.

In the example below, each symbol has an identical number of stops on the reel – 1 for the lucky seven, 3 for the plums, 5 for the lemons, and 7 for the cherries.

Of course, it is also possible to design the game so that there are 4 random numbers for lemon 1 on the first reel, 5 numbers on the second reel, and 6 numbers on the third one if this yields the odds you are looking for. It all comes down to the odds you want to assign to the game.

In today’s slots with mechanical reels, the blank spaces between the symbols are stops as well. We used only symbols in our example for simplicity. The probability of winning the top-paying combination of three lucky sevens is 1 in 1,000. Consequently, such a game will not yield a huge jackpot even if the designer significantly decreases the payouts of other matching combinations.

When symbols are mapped on virtual reels, the probability of winning with three lucky sevens dramatically decreases to 1 in 125,000.

This enables the game to award top prizes that reach thousands of credits while leaving room for more payouts with other matching symbols. Thanks to symbol mapping and virtual reels, slot developers are now capable of designing slots with lower variance. This is possible by decreasing the game’s jackpot and increasing the payout of low-paying winning combinations.

The Payline

The number of paylines is easily one of the most important features to consider when choosing which slot to play. A payline, or win line, is a pattern of matching symbols on the reels that awards a payout. Paylines can run across the middle of the reels, diagonally, in zig-zag patterns, and so on.

Classic slots with three reels have a limited number of paylines, while their advanced video cousins boast multiple lines whose number can reach 100 in some games. In slots with five reels, there is no need to land identical symbols on every single reel to win.

Some video slots award payouts for aligning three, or even two, matching icons on a payline. The more matches you score, the bigger the payouts you receive. In some games, top-paying symbols return smaller prizes for two identical symbols only.

More often than not, the rules stipulate that the symbols must appear from the leftmost to the rightmost side of the reels. You normally receive nothing for four cherries on the second, third, fourth, and fifth reels if the symbol is absent from the first reel. The paylines in some games pay in both directions. You collect a monetary prize as long as you have like symbols aligning on any of the paylines.

Playing multi-line slots is preferable because you can win with several paylines on the same spin. The more paylines there are, the greater your chance to collect a prize. With that said, it is essential to clarify that you need to place a bet on a win line to activate it. Otherwise, you will not pocket anything even if identical symbols land on the payline.

The number of paylines is fixed in some slots. Players cannot activate or deactivate lines but have to cover them all with one or more coins on each spin. Suppose you play with 20 fixed paylines where you can bet between 1 and 5 credits per line. The minimum bet you can place will amount to €0.20 per spin, provided that you play at the first level, betting 1 coin per line with a denomination of €0.01.

In other games, you can adjust the number of paylines you play per spin by deactivating some of the available lines. This is not necessarily the wisest course of action because winning combinations do not pay when they land on deactivated paylines.

The Paytable

The paytable is where reel spinners will find all the important information about the slot they are interested in. It contains all winning combinations of symbols alongside the number of credits each can earn you. Additionally, the paytable lists the bonus features incorporated into the slot and the conditions players must meet to trigger them.

In most cases, the listed coin payout values are based only on the first betting level, where you wager one coin per line. You can usually open the paytable by clicking or tapping the info button on the main game screen.

Below is an example with the paytable of NetEnt’s Starburst slot, where you need a minimum of three identical symbols on one of the 10 paylines to win a prize. The game has five betting levels, allowing you to wager up to five coins per active payline. Because paylines cannot be deactivated here, a single spin will cost you a minimum of €0.10 (€0.01 x 10 paylines).

If you inspect Starburst’s paytable closely, you will notice that some winning combinations do not fully cover the cost of the spin. Such is the case with the purple and blue gemstones that return a minimum payout of 5 credits for 3 matches at the first betting level.

As you can see from the image, we won with a €0.20 bet of two coins per line (2 coins x €0.01 x 10 lines = €0.20). A combination of 3 blue gems returns 5 credits per coin wagered. Since we scored wins on paylines 1, 3, 5, 7, and 8 at the second betting level, the spin resulted in a profit of 5 x €0.05 x 2 coins = €0.50. Not the most impressive win, but it still suffices to show you how multiple paylines and bet levels work.

Starburst has a more basic paytable than those available in advanced slots. Some games offer a higher winning potential, with more paylines, symbols, and winning combinations. Many slots use additional playing card symbols (usually 10, J, Q, K, and A) for their low-paying combos.

Starburst has only one special feature (up to 3 free re-spins), although there are games with multiple features like free spins and bonus games. The maximum number of credits you can wager per spin is 100 coins, but this limit can be significantly higher in other slots where players can risk 400 or even 500 coins.