10, active PFC What are the characteristics? A: active PFC input voltage from 90V to 270V; power factor above 0.99, and has low loss and high reliability, etc.; can be used as auxiliary power supply, eliminating the need for auxiliary power transformer; output DC voltage ripple is small Therefore the use of active PFC power supply does not require the use of large-capacity filter capacitors. 11, passive PFC What are the characteristics?
A: passive PFC inductor compensation method commonly used by the AC input of the phase difference between the fundamental current and voltage reduced to improve power factor, passive PFC power factor is not very high, only 0.7 to 0.8, and heat relatively large.Mini Wireless Keyboard
12, turn off the power of the software features implemented by what? A: The power of software power off function is the PW-OK circuit. PW-OK standby to host the zero level of output power self-test signal, the host stops working on standby.
Controlled starts, PW-OK in the switching power supply output voltage and then delay a few hundred milliseconds by the 0-level jump from +5 V,Patch Cord Manufacturer
output high level signal to the host. The signal power is equivalent to AT PG signal. Host to detect well-PW-OK signal power start system. In the case of the host running when mains power failure or shutdown, PW-OK output signal than the ATX power supply +5 V output voltage disappear a few hundred milliseconds in advance to notify the host before the trigger system automatically shut off the power to prevent a sudden fall power the hard disk heads to move the landing zone was too late scratch disk.
13, what is the conducted interference? A: The transmission is used to measure electronic interference during operation of the entire network to send electronic interference signal size concept. All electronic products will be in power when the issue of interference signals on the grid, if the interference signal is too large, it will affect the quality of the electricity grid,Cable Manufacturer
which interfere with the normal operation of other appliances. Therefore, most electronic products, the state conducted interference indicator has a mandatory, prohibiting conducted interference is too large production and sales.
14, power supply test in which the more important projects? A: There are cross-load, surge, voltage, ripple noise, output short circuit, over power, efficiency, power factor, response time, timing, noise, radiation, conduction, leakage current, high and low temperature testing. 15, what is the inrush current? A: The power-on surge current refers to the moment, the peak current into the power supply. Because the input filter capacitor for rapid charging, so the peak current is much greater than the steady-state input current.
Should limit the AC power switch, bridge rectifier, fuse, EMI filter components can withstand the surge level. Loop repeatedly switch,electric welding machine manufacturer AC input voltage should not damage the power supply or cause the fuse has blown.
16, what is the conversion efficiency? A: Because the power at work, some electrical energy into heat loss out.
Therefore, the power must minimize heat loss. Conversion efficiency is the output power divided by input power percentage.
Version 1.3 under full load power requirements for the minimum conversion efficiency of 70%. Version 2.0 is the recommended conversion efficiency increased to 80%. 17, power factor and efficiency What is the difference? A: Although the power factor and power conversion efficiency of the utilization of all means, but the difference is great.
Simply put, power factor losses due to the burden of the power sector, while the conversion efficiency of the loss is the user's own burden. Can see, power factor, EMI are all on the national grid protection.