Agency certification

UL, CSA and TUV safety agency test specifications, such as component spacing, Hi-Pot high voltage isolation, leakage current, circuit board flame retardant, and high temperature resistance rating.


Auto range

Automatically sense the input voltage and adapt the power supply itself to the appropriate range (115V AC or 230V AC). No manual switch is necessary.


CFM (cubic feet per minute)

The typical value of the fan passing through an ordinary ATX system ranges from 25 to 35 CFM.


Signal loss

A condition allows the input voltage to drop below the specified minimum input voltage to the power supply.



The ratio of output power to input power, expressed as a percentage.


Electromagnetic interference (EMI)

EMI, which is the noise generated by the switching operation of the power supply, can be divided into conducted EMI and radiated EMI. Conducted EMI, which is fed back to the power line, is usually suppressed by an EMI filter placed on the input to the power supply. EMI radiation, the radiation into free space, is usually suppressed by the switching power supply in the case of housing and metal. The United States Federal Communications Commission governs conducted and radiated EMI emission levels.


Hold time

The AC input power below the time period during which the power supply can maintain the maximum DC output power output regulation loss.



When a fault is detected, the power supply usually shuts down by itself to protect its electronic load. Even when the fault condition disappears, the power supply does not resume its normal operation unless manual or electronic intervention is called. Manual intervention can be achieved by plugging and unplugging the AC input power supply. Electronic intervention can be achieved through electronic signals in the server system.


Power regulation rate

The change in the output voltage due to the change from the minimum to the maximum input voltage within the specified range is expressed as a percentage of the nominal output voltage.


Load Regulation

The change in output voltage due to the change in output current from the minimum to the maximum within the specified range is expressed as a percentage of the nominal output voltage.


Mean time between failures (MTBF)

The measurement according to MIL-HDBK-217 is based on the relative reliability of the power supply when measured or calculated.


Monotonic transition

The waveform goes from one level to another in a monotonous manner, without intermediate oscillations crossing itself.


Business Scope

The specified minimum and maximum allowable input voltage/frequency and ambient temperature are safely operated within the specified range.


Over current protection (OCP)

A circuit that protects power supplies and electronic loads from overcurrent, including short circuit protection (SCP).


Overvoltage protection (OVP)

A power supply whose output voltage exceeds the specified limit when the circuit is closed.


PFC (Power Factor Correction)

Power factor (PF) is the ratio of true AC input power to apparent AC input power. A higher PF means more efficient use of electrical energy. PFC shapes the input current so that the phase of the current waveform is the sum of the voltage waveform of the input voltage with the same shape. The power factor without PFC is about 0.55 to 0.60, while PF and PFC are about 0.95 to 1. PFC can reduce the input current and harmonic current, thereby reducing the copper loss of the power line.


Power is OK (PWOK)

The logic output provided by the computer system of the signal, all the DC output voltage is within a specific range of the power supply.


Ripple and noise

Peak-to-period signal and random noise, which is the peak amplitude superimposed on the DC output voltage by the switching action of the power supply, are usually measured in the bandwidth of 10 Hz to 20 MHz and designated as the nominal 1% DC output voltage.


Rise Time

The rise time is defined as the time required for any output voltage to rise from 10% to 90% of its nominal value.



The condition on which the input voltage is lower than the specified minimum input voltage.


Standby by voltage

The output voltage is this whenever AC power is input to the power supply.



The condition on which the input voltage exceeds the specified maximum input voltage.


Transient response

The required output voltage time is returned within the envelope with the following 50% load change.50 adjustment