Basically, a slot machine is a device that spins a wheel or reel. The player bets money into the machine, and hopes to win a prize. A slot machine can be a physical machine or an electronic machine.
Traditionally, slot machines have been mechanical, which uses a spinning wheel and reels. Some modern machines have microprocessors that assign different probabilities to different symbols.
Some video slots also include interactive elements, such as a game that simulates a jackpot, or bonus rounds that award additional payouts. These bonuses are usually aligned with the game theme.
For example, the game Reel ‘Em In was the first video slot machine with a second screen bonus round. It was developed by WMS Industries in 1996.
In addition to the traditional mechanical slot machines, manufacturers began incorporating electronics in the 1980s. Initially, microprocessors used a number of features to control payout. The amount of coins in a payout reservoir was monitored by the microprocessor. The game software could be stored on a DVD or non-volatile random access memory.
Modern slot machines no longer have tilt switches. The original machines used a side lever that triggered an alarm if the switch was tampered with.
The number of credits listed on the pay table is usually indicated on the machine’s face. The payout is based on the pay table, and credits are awarded when symbols align on a pay line.
Usually, the number of symbols displayed on a slot machine is based on the theme of the game. Some symbols may only appear on certain reels, while others may appear in many combinations.