DC Voltage Power Supply Using The LM317

DC Voltage Power Supply: Commonly we use a fixed voltage regulator when we have to fix voltage for any circuit. Many times we need a variable voltage power supply to control the voltages according to our choice and here we needed a variable voltage power supply. LM 317 is the best choice for this purpose, Drawback of lm 317 is that it can control and can be used in very low amperes, In this article, I will clarify how someone can someone make a power full DC variable power supply with the use of with the addition of one more transistor.

DC Voltage Power Supply Using The LM317

Variable Voltage Power Supply LM317

The LM317 is a fully adjustable positive voltage regulator that can control 1.5 amps with an output voltage from 1.25 volts to 30 volts. By using the ratio of two resistances one of a fixed value and the other variable or both fixed,.we can set the output voltage to our desired level. Total input can be given to this regulator from 3 to 30 volts DC.

Variable Voltage Power Supply Using LM317

LM 317 Regulator For DC Voltage Power Supply

LM 317 voltage regulator

It is a type of positive-linear-voltage regulators used for voltage regulation, designed by Robert C in 1976 while he worked at National Semiconductor.

It is a three-terminal-adjustable-voltage regulator and is easy to use Because it has only three terminals to use. It is majorly used for local and on-card regulation. If we use fix resistors with this regulator then it can also be used as fix output like 7805,7806,78XX and so on,


Variable DC Supply using 2n3055 transistor

The above-given circuit can control on 1.5 amps DC current but sometimes we have to control more amps to control our DC appliances. To control powerful appliances we must have to use a powerful power supply so now we convert our supply in power supply with the help of another transistor 2n3055, It can control 15 amps DC current ranging 6094a5c.

voltage regulator using lm317

An alternative circuit is shown above for an adjustable power supply with LM317 and parallel-connected NPN power transistors. It can control 15 Amps according to my knowledge and if someone needed more amps then another circuit design is also given below.

variable power supply

This circuit shares a double amp and that is why you can control more amp with this circuit anyhow if u find any mistakes in this circuit then please share your knowledge with me I will be great full to you.


I made the first one circuit with one transistor (2n3055) that works very perfectly but when I used it with two transistors it did not work. what is a problem I did not understand if any expert read my post plz must guide me and my viewers with an explanation?

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