Q:Why some switch power there are two switch tube? Two transformers, one big and one small series

With a small push large, compound use, increase the power supply

Q:What is the PWM high-frequency switching power supply

That is, the DC power to a high-frequency chopping to a pulse when the pulse is not broken when the wave will be able to get such a smooth waveform, such as sine wave Through the control of the pulse width in order to achieve the size of the output power control, such as sine wave peak width of the widest width and smaller pulse width when the narrow

Q:Switching power supply and communication power difference

Communication power is the power of the communication equipment. Can be a battery, 220V AC, generators, dry batteries, cell phone batteries, etc., because it is used for communications equipment, it is generally through the high-frequency oscillation of electronic circuits (switching power supply)

Q:What is the working principle of the power switch?

But we also note that 300V DC power added to the standby power switch and standby power switch transformer, the standby power switch is designed to self-excited oscillation mode, standby power switch immediately start working in the standby power switch transformer times Level output two sets of AC voltage, the rectifier filter, the output + 5VSB and +22 V voltage, +22 V voltage is designed for power supply internal control IC power supply. + 5VSB voltage for the standby voltage, the output to the motherboard. When the user presses the power button of the chassis, the motherboard sends a power-on signal to the power supply. At this time, the (green) color line is low, the IC's internal oscillation circuit starts immediately, generates the pulse signal, The signal is applied to the base of the main switch tube by pushing the transformer so that the main switch is operated in the high frequency switching state. The main switch transformer output voltage of each group, after rectification, filtering and regulation, get each group of DC voltage, the output to the computer host. But the CPU on the motherboard at this time has not yet started, must wait + 5V voltage from zero to 95%, IC detection +5 V rose to 4.75V, IC issued P.G signal, the CPU starts, the computer work properly. When the user shuts down, the green line is at a high level, the IC immediately stops oscillating, the main switch tube because there is no pulse signal and stop working. -12 to +3.3 of the voltage drop to zero. The power supply is in standby mode. Protection circuit principle brief: In the normal use of the process, when the IC detects the load is in: short circuit, overcurrent, overvoltage, undervoltage, overload and other state, IC internal signal, so that the internal oscillation stopped, the main switch tube because there is no pulse and stop working The So as to achieve the purpose of protecting the power supply.

Q:Electronic transformer, inductive transformers, switching power supply transformer What is the specific difference? What kind of situation which the election of a transformer? 5 Halogen spotlights require dimming control, LED lights have to dim, Will the high school electronic transformers, switching power supply can be used with dimming?

Remember: Transformers and regulators are different concepts. Transformer output is generally constant pressure, is not continuous adjustment.

Q:Would like to ask the switch power supply in the end is what role?

Switching power supply is the principle of alternating current frequency into DC, and then convert DC into high frequency AC, through the switching transformer, feedback regulator and other processes into the voltage you need, through rectification, filtering, and then converted into DC The process, and MOSFET throughout the process through its continuous opening and closing, so that high-voltage DC into high-frequency AC process.

Q:Isolation switch power supply and non-isolated switching power supply advantages and disadvantages,

First of all from the name can be seen, isolated switching power supply is isolated, that is input and output is not connected (in fact, there is a small capacitor between input and output), even if the power is broken, the input voltage is not Will be added to the output, due to the input and output isolation, the input part of the noise will not be transmitted to the output part (non-switching noise), isolated power supply mostly AC-DC, is AC to DC, can also be used for DC to exchange (such as Inverter), the voltage output is generally fixed or adjustable range is relatively narrow, but the output voltage is very wide, such as the input is 220V AC, the output can be 3V, it can be 30V, it can be 3000V, it can be 30000V Non-isolated switching power supply is generally DC-DC, that is, we often say that the DC to DC, the general non-isolated power supply efficiency than isolated power supply efficiency, but because the input and output are connected between, so there is a total (BUCK) If the switch tube breakdown, the input part of the voltage will pass to the output, the boost type of the type of noise, that is, when the input voltage is noisy, it is easy to pass to the output, (BOOST) If the circuit does not work, the input voltage will go straight to the output, whether it is buck or boost type, adjustable range is wide, step-down type can generally from 0 to the input voltage (due to the circuit Voltage drop, actually less than the input voltage), step-up type can be from the input voltage to several times higher than the input voltage There is also a non-isolated circuit up and down (SEPIC), the input voltage can be higher than the output voltage, but also lower than the output voltage, and the output voltage adjustment range is relatively wide

Q:Find the correct use of this constant voltage constant current switching power supply, and the current adjustment method

Usually we are talking about the load regulation rate is generally for constant voltage type power supply, when the input voltage is constant, the load changes from zero to the rated value, the output voltage changes. Usually expressed as a percentage

Q:Switching power supply maintenance methods can be divided into several steps

3, then, for the PFC circuit with the power supply is required to measure the voltage at both ends of the filter capacitor is about 380VDC, if 380VDC voltage, indicating that the PFC module is working properly, and then detect the working status of PWM components to measure its power input VC, Reference voltage output VR, start control Vstart / Vcontrol terminal voltage is normal, the use of 220VAC / 220VAC isolation transformer to the switching power supply, with the oscilloscope to observe the PWM module CT end to ground waveform is linear good sawtooth or triangle, such as TL494 CT side for the sawtooth wave, FA5310 its CT side for the triangular wave. Whether the waveform of the output terminal V0 is an ordered narrow pulse signal.

Q:How are two ac inputs connected to the socket? G1 and G2 and FG is not connected together, and then connected to the chassis? thank you

According to your instructions to write your power is two output, Two AC terminals through the power cord can be directly connected to the socket, no positive and negative points; FG is the power and the earth (that is, the chassis) connected; In the order you say, G1 and V1 are a group (G1 is this negative, V1 is positive); G2 and V2 are a group (G2 for this road negative, V2 is positive); Note: FG and G1, G2 can not be mixed!