What is the Producer Surplus and how may this Happen?

-This is when the Producer gets More Money for a Product [$50] than they'd Hope, and Accept for [$30] -So Above the Producer Surplus is $20 - This is the Difference between the Price that a Producer is willing to Supply, and the Price they Actually Receive [Equilibrium Price] -This may happen as Different Producers will have Different Costs when making their Goods