Q:Material: 3.7V, 5V DC power supply, the general number of two transistor, any resistance to a number of resistance, require 1.2V DC voltage, and power requirements as large as possible. LM317, LM385 this thing is good, but the hands did not, do not want to run this trip because of this thing to buy. The The Can I use multiple diodes in series to get 1.2V? Does this offer high power? Or is there any other good advice? Hope that the circuit design as simple as possible, I hope we can help.

The simplest is the diode buck, but the load current changes in the larger case, the stability is not too high. The best is to use MOS regulator for the regulator, the circuit is slightly more complex.

Q:Use 7812 to make a positive 12V DC power supply Is 220V AC voltage correction 12V

1st floor ny_peter circuit diagram is basically correct, but the transformer secondary voltage setting is too high, which will make the power efficiency is low, in the larger output current regulator serious heat.

Q:How does the output resistance and ripple factor affect the regulated power supply

When the load changes (from no load to full load), the output voltage Usc should remain essentially unchanged. The performance of the regulated power supply can be characterized by output resistance. The output resistance (also called equivalent resistance) is denoted by rn, which is equal to the ratio of the output voltage change and the load current change. Rn reflects the load changes, the output voltage to maintain a constant ability, rn smaller, then Ifz change the output voltage changes are smaller. Excellent performance of the power supply, the output resistance can be as small as 1 euro, or even 0.01 oh. The so-called ripple voltage, refers to the output voltage of 50 Hz or 100 Hz AC component, usually expressed with a rms or peak. After the regulator, can make the rectified filter after the ripple voltage greatly reduced, the inverse of the inverse ratio of the regulator S.

Q:I have a 220v buck regulator output 12v power supply, how to calculate its output power? I measured with a digital multimeter output port voltage is 12v, and then transferred to the current block, directly to the meter measured power output port, did not show, is not the way to measure the current is not right? How to test specific Or there is no way to calculate the power of the power, I now know the voltage is 12v, but the current does not come out ah? Put away How do I know the power of my regulated power supply?

First measure the current is required ammeter and load in series; Second, the different digital table may be different, and some digital table current block exclusive of an output plug, please note whether the right! Voltage is generally not measured, are almost the same as the nominal power = voltage in the X current, and the current and load, if it is no load when the current = 0, so to measure the current must be in the case of a load Measured out.

Q:Ultra-low voltage automatic power supply how to use

` And then one is your regulator is broken! There is a load and you do not match the regulator, the regulator can not drag the load! Question: I was the regulator of the 3000V ``

Q:Members help me to explain the role of the various components in detail. The There D5 regulator is 21V why the output is 20V, they said to reduce the UBE0.7V pressure drop. I do not understand, why should subtract UBE ah? The more detailed the higher probability of adoption. The Remember the details. The The Thank you all the teachers. The ? Mainly three-tier tube is how to complete the regulator?

You are right, the current is so gone. Regulator tube can indeed be seen as a voltage source, but the internal impedance is very large. By reason, with the regulator can also be directly for the power supply, but then, the resistance is the current limiting resistor, the output current will be small, may not meet your requirements. With the transistor as a regulator tube, a big reason is to reduce the power supply resistance, increase the power output capacity (current).

Q:Switching power supply with load capacity difference is what reason. My switching power supply output is 2A-24v. The output is not connected to the output is 24v. Connected to the 24v -5w lamp only 2v voltage. Even the switch power indicator light is not bright. What 's the matter?

The biggest possibility is that the output capacitor is bad, deteriorated. As the switching power supply for a long time to work fever, so that the capacitor electrolyte dry, so the capacity decline, ESR (equivalent resistance) rise, simply say that its filter capacity decreased, so it can not be properly loaded, the use of low ESR specifications After the capacitor can be replaced. But must be low ESR, otherwise the switching power supply because of high frequency, high ESR of the ordinary capacitor may be due to serious fever burst.

Q:With the transformer why DC power supply, DC power supply is 220VAC input, output 24VDC; transformer is 220V / 24V. Is this not repeated?

You'd better describe the problem in detail. Normally, the transformer changes the voltage of the alternating current, that is, the input is alternating current, the output is also alternating current. But we usually need electrical equipment DC power supply, so the need for rectification after the transformer, filter, regulator and other processing circuit, to provide to the electrical equipment.

Q:What is the working principle of an adjustable DC regulated power supply?

Rectifier and filter circuit works, characteristics and calculation of the main parameters. 1 silicon voltage regulator diode regulator circuit 1 Zener diode characteristics The use of silicon diode reverse breakdown characteristics, can produce a zener diode. The general diode is not allowed to work in the reverse breakdown area, because the reverse current IR is large, the breakdown power consumption P = IR ?? UBR is very large, beyond the maximum allowable diode power loss, the diode Will be burned. Zener diode junction area of the larger, allowing greater power consumption, as long as the breakdown power consumption does not exceed the allowable value, the Zener diode will not burn. For example, there is a Zener diode power consumption PZ = 500mW, reverse breakdown voltage UBR = UZ = 10V, then the maximum reverse current

Q:Is the switching power supply output from a regulated or pulsed power supply?

The pulse width at both ends of the transformer lead varies with the load or the pulse width which varies with the load and then becomes the pulsating DC through the rectifying element and then the pulsating DC becomes the flat by the discharge of the capacitor DC voltage through the regulator circuit to ensure the stability of the output so the result is the power supply voltage regulator phone is not the same as most of the regulator is also a cross-flow function there is no regulator of the DC (this is the kind of transformer, But 50HZ AC transformer after the rectification of the basic) out