Modern casino slot machines are controlled by computer software, and the win %s are pre-programmed into the game software.
Casino slot machines have Random Number Generators which are continually generating combinations, even when the machine is not active.
Running side by side with the random # generator of the casino one-armed bandit is the payout %.
The payout percent controls just how much the one-armed bandit will payout, for e.g. the payout percentage could be 90%, which means the slot machine will pay ninety percent of all the bets played, and the casino simply gets to keep 10 percent.
This does not imply that every time you bet ten credits you will receive nine in return – where is the fun … thrill in that? Instead, the casino slot machine just will not pay out for a bit, and then suddenly jump on a hot streak and you might catch the big pot prize.
The payout %s will vary between the different games and several of the notably acclaimed casinos, such as Golden Online Casino, which tenders a payment of up to 95 percent!
This means that, in essence, the one-armed bandit takes all the dough played into it and pays it out to a couple of lucky winners. The casino only gets to keep a fairly minute per cent of all the gambles allocated.
The casino slot machine software controls each and every part of the machine, from the blinking lights to the rolling of the reels.
When you hit spin on the slot machine, a combination is formed by the RNG which relates to the pictures on the reel.