How slots work
Playing slots
ELECTRONIC MACHINES
Electronic slots
Eventually, inevitably, all this thrashing of metallic machinery gave way to the electric age.
Outwardly similar in appearance, the electric machines' reels are spun by motors and the stoppers activated by solenoids.
To the player it's the same game. Just that the clanking and clunking has been replaced by flashing lights and a fanfare of music when it registers a win.
To do this, (as with the mechanical version), when the reels stop, the electric slot machine has to 'read' the reels before it pays out.
How it does this can differ from machine to machine. In one of the simplest designs, a jackpot is detected by measuring the depth of notches on the discs that drive the reels.