If you are the noncustodial parent, you can receive the personal exemption of $4,050, which may increase your refund because it is used to lower your taxable income. How much it helps you depends on your taxable income and tax rate.
The credit you receive is the Child Tax credit, which ha a maximum of $1,000, and can be used to decrease any tax you owe. That credit can become the Additional Child tax Credit depending on your income and tax owed. See the line references above.
There's no fixed maximum for claiming a child, although many people seem to think there is. Like most tax situations, the answer is that it depends on many other other factors in your specific return.
