The first slot machine—the Card Bell—was created by Charles Fey in 1898. Using painted-on symbols inspired by playing cards, it would soon give way to a more patriotic-themes version known as the Liberty Bell. Fey made money by renting these devices to bars and taverns, receiving half of the profits.

The slot games were an immediate success, and Fey received offers from numerous companies wanting to purchase the manufacturing or distribution rights. When he declined their offers, they went in search of someone who could duplicate the machines.

In 1907, a Chicago inventor named Herbert Mills created a similar slot known as the Operator Bell. It was the first game to use fruit symbols, and it soon enjoyed a presence in bars across the United States. In some states, winning players received coins as a prize. In states where gambling was illegal, however, payouts often consisted of food, alcohol, or cigars.

Mechanic slots continued on for decades, but the industry took a major leap forward in 1963 when Bally unveiled the first electronic version of the game. Its popularity was immediately noticeable, and it would soon dominate the casino landscape.

The first video slot appeared in 1976 at the Las Vegas Hilton, and it spread throughout the world in no time at all. A decade later, the first progressive jackpot game arrived on the scene, and that’s when the popularity of slots began to skyrocket.

Less than 10 years later, another innovation came when Microgaming Software created the first online casino. Slots were an integral part of this development, and they continue to be the biggest source of casino revenue—in both virtual and land-based establishments—as of this writing.

Whether you enjoy playing slots at a brick-and-mortar casino or in the privacy of your own home, you’ll encounter several types of games to choose from. They might all seem the same at first glance, but reading this section should inform you of the differences. Keep in mind that some games also fall into more than one category.

The driving force behind modern slot machines is the random number generator. This piece of technology is present on both online and land-based slots, and it ensures that each spin is independent of all others.

As soon as a machine becomes active, the RNG begins to constantly generate numbers at a rate of hundreds or even thousands per second. When a player makes their wager and presses the spin button, the most recent batch of numbers is taken in order to determine which symbols appear on the reels.

This means that the spinning reels provide nothing more than a visual indication of what digits were selected by the random number generator. As soon as the button was pushed, the outcome was determined faster than the human mind can process.

Some symbols on a slot machine appear more frequently than others, which mean a game is “weighted.” This is common to all slots, otherwise the major symbols would appear more frequently and the casino would surely end up losing money in the long run.

Slots are also programmed with a certain payback percentage, which is the amount paid back over the life of the machine. A slot with a 98% payback can be expected to deliver 98 cents for every dollar wagered, although this can fluctuate greatly during the short term.

Some players still prefer to game on a physical machine, while an increasing number swear by the virtual options offered at online casinos. In case you’ve never tried the latter, here are a few reasons why you might prefer the experience:

It’s important to note that no strategy exists for consistently beating slot machines. These games are entirely random, so you may win big during one session and then lose it all the following week. There are, however, a few things that you can do to maximize your time spent in front of the slots.