"Tiny Cooling Fan" contact load refers to the capacity of the contacts. When converting relay contacts can withstand a certain voltage and current. Therefore, when using the relay contacts should consider the voltage and current through the contacts of the relay contacts can not exceed the load capacity. For example, there is a relay contact load is 28V (DC) × 10A, show "Tiny Cooling Fan" relay contacts can only work in 28V DC voltage on the circuit, the contact current is 10A, more than 28V or 10A, will affect relay normal use, even burned contact relay selection _ relay coil power choices. This refers to the "Tiny Cooling Fan" relay coil using a direct current (DC) or alternating current (AC). Typically, beginners in electronic production activities are based electronic circuits, and electronic circuits often use DC power supply, it must be using a DC voltage relay coil.