A measuring apparatus includes a first connector connected to a storage controller through a second connector of a motherboard. A control circuit receives voltage signals from the storage controller and converts the voltage signals to hard disk drive (HDD) power signals. A detecting circuit includes an AND gate and first to fourth resistors. A first input terminal of the AND gate is grounded through the first resistor and connected to the control circuit through the second resistor. A second input terminal of the AND gate is grounded through the third resistor and connected to the control circuit through the fourth resistor. An output terminal of the AND gate is connected to a measuring pin of the first connector. The AND gate receives the HDD power signals and outputs a power good (PWG) signal to the measuring pin of the first connector to be measured.