The GPT-9000 Series supports the major test items among all the needed for the compliance of the safety standards such as IEC, EN, UL, CSA, GB, JIS and other safety regulations. The GPT-9904 is capable of performing both AC and DC withstanding tests. The GPT-9900 series safety tester follows every good feature and advantage of the GPT-9800 series. The high-efficiency PWM amplifier is the core of GPT-9900 platform design to impede the influence from the voltage fluctuation of input AC source. The output voltage is automatically cut off (within 150?s) upon the detection of an abnormal output voltage or a trip of current limits during test to protect the operator from hazardous injury. The GPT-9900 series automatically discharges the DUT after each test to eliminate excessive voltage that remains on the DUT.