The PAD-L Power supply is designed for high operation reliability and excellent electrical performance. It is a universal-purpose industrial power supply which can be used as a variable power source for research and development, or as a fixed power source for long time aging test. Features of the PAD-L Power Supply can be summarized as following. 1. Improved power factor at low output voltages A choke input system is used for the rectifier filter circuit, thereby reducing the apparent input current and improving the power factor. This led to a smaller power transformer and consequently to a compact and light power supply. 2. Less waveform distortion caused to the AC input line: As the choke input system is used, the input current waveform is less distorted with harmonics, thereby reducing waveform distortion to the AC input line. 3. Excellent temperature coefficient: Very low temperature drift characteristics of 50 ppm/⁰C is attained by using premium-quality parts, improved circuits, and forced air cooling. Time-elapse drift (aging drift)’ also is very low. 4. Fast transient response: A wide-band error amplifier is used to ensure stable frequency - gain, phase characteristics.