The aim is to build a high current bench power supply without noise on the output unlike the. Description the circuit is based on lm317 positive and lm337 negative voltage regulators. The first circuit well look at is the lm317 based voltage regulator. How to use lm317 for making a variable power supply. For this purpose we have used two lm317 ics, one is used to control the voltage and the other is used to limit the current. Where we are using 4 diodes and those rectifies the output of the stepdown transformer, that stepdown the 220 ac volts to 12 ac volts. In this tutorial we will show you how to get the variable regulated voltage from the lm317 ic. Building a power supply is a good way to put into practice many of the ideas we have been studying about electrical power so far. The value of voltage would correspond to what voltage level was needed. The circuit is based on lm317 positive and lm337 negative voltage regulators. Lm317 adjustable voltage regulator complete tutorial with practical experiments. Care must be given to identifying the proper components and in good soldering habits.
Abstract our final project is an attempt to integrate two different charging ports standard usb 2. Although you could use this design to deliver 20 amps with almost no modifications and with a proper transformer and a huge heat sink with a fan. In this circuit, the input line power supply is designed for 240vac. The output from an ordinary power supply is fed to the voltage regulating device that provides the final output. Dual adjustablevariable power supply circuit using lm317. This is the first dc power supply in my life that made to use in many projects. Simple lm317 power supply with current limiting hackaday. These lab power supplies are very good for testing a circuit in the lab but not. This is an easy to make power supply which has stable, clean and regulator 028v 68 amp output voltage. But in many electronics circuits it very important to keep the contact dc power supply irrespective of variant ac mains supply. This article describes you how to design a variable power supply circuit which will provide 0 to 28v at 6 to 8 amps. By using two 2n3055 transistors we become more then 2 times the amount of amps then the power supply delivers, making it real though to brake.
This ic is normally available in to220 package and. Here we make a variable dc power supply and the main working principle of this project is full wave rectification which is done by bridge configuration. Here well try to understand how to construct a simplest power supply circuit using the ic lm317. This is a simple, but lowripple power supply and an excellent project if youre. I am building two of these, with one slotting into my main power station, the powerstation2. Especially when its a high power supply that can handle as much as 20amps of current. Regulated power supply circuit diagrams and working. One of the main disadvantages of using the lm317t as part of a variable voltage power supply circuit to regulate a voltage is that as much as 2.
This 515v regulated power supply project is a simple power supply that has a variable dc voltage range from 5v to 15v. Variable dc power supply is one of the projects that every electronics student should build. Here, in our circuit the ic u1 is used to control the current and. Variable dc power supply using lm317 variable dc power supply. Lm317 is a three terminal adjustable voltage regulator. I hereby certify that the work is being presented in this report work entitled. Variable power supply using lm317 voltage regulator electrosome. The output of the transformer is rectified using a full wave rectifier to bypass the unwanted. If you have experience in soldering and wiring technique, you should have no problem in the assembly of this kit.
Lm317 series of adjustable 3 terminal regulator is capable of supplying in excess of 1. I personally love this ic yes, its not a transistor a lot, not because it server it purpose well, but because its cheap, easy and never disappoints you while making a regulated dc power supply. A variable power supply circuit is built with variable positive voltage regulator lm317, cmos decade counter ic cd4017, timer ic ne555 and fixed negative voltage regulator lm7912. The ac supply is fed to the transformer which is stepped down to 12v ac. How to make a simple adjustable power supply using. High current variable voltage power supply project part. Lm317 adjustable voltage regulator complete tutorial with. The lm317 circuit is shown in the below figure is a t y pical configuration of the lm317 voltage regulator circuit diagram including the decoupling capacitors. Variable voltage power supply circuit using the lm317t voltage regulator to produce a 1. Presented here is a 050v, 1a variable power supply that has been designed using positiveadjustable voltage regulator lm317 ic.
Thus this simple tweak using a few 2n3055 transistor transforms a ordinary lm317 variable regulated power supply into an awesome high current lm317 regulated variable power supply unit. This voltage regulator is exceptionally easy to use and requires only two external resistors to set the output voltage. You are about to report the project simple lm317 power supply. In a variable power supply, automated detection of the device is.
The 317 is a variable voltage regulator with adjustable 3terminal positive voltage pins designed to supply more than 1. It is ideal for those who want to adjust voltage from 1. This 20 amp variable power supply varies its output voltage from 1. But what if need to vary the power supply voltage, so here we have variable voltage regulator ic lm317. Fortunately it is easy to construct a stable power supply using negative feedback. Lm317d lm317, ncv317 voltage regulator adjustable output, positive 1. Variable power supply using lm317 the capacitance c3 bypassing the adjust pin to ground will improve the ripple rejection capability while the diodes are used to protect the regulator from excess flowing through it if a battery or any other voltage source is connected across the output terminals of the regulator. The ic lm317 is so versatile that an almost unlimited number of different, small, high grade power supply circuits can be built using it. It can supply current up to a 400ma to power the various circuits for your electronic projects. Lm3x7 series of adjustable 3 terminal regulators is capable of supplying in excess of.
Working of variable power supply with digital control. In this project a 050v, 1a variable power supply has been designed using positiveadjustable voltage regulator lm317 ic. The configurations can be introduced for different applications for upgrading an existing unit with features that would virtually make it indestructible. Heres how to build your own adjustable power supply based on lm317. Download as docx, pdf, txt or read online from scribd. Your variable voltage supply is based on a sophisticated and very effective integrated circuit used. Assembly of your xp15k regulated variable power supply kit will prove to be an exciting project and give much satisfaction and personal achievement. The voltage output is varied by using the potentiometer vr1. High current dc regulated power supply circuit with lm317.
We have 78xx 7805, 7806, 7812 etc series voltage regulators for positive power supply and 79xx for negative power supply. There are 3 pins and the body is the same as the regulated ic, 7805 but it can provide to 1. The main parts required for the construction of the variable regulated power supply are listed below along with their specifications. Most often, power supplies are used in consumer electronics to provide a. Design a simple dc power supply michigan state university. Build a 5 amp portable power supply with an lm338 regulator. The main objective of our 12v power supply circuit is to control the voltage and current for the battery so that it can be charged in the best possible way. Adjustable lm317 voltage regulator circuit with working. The kit takes a 9v battery by default and i wanted to power it from the. Build an adjustable 230 volt power supply with the lm317. This lm317 circuit is capable to provide variable dc power supply with output of 1a and can be adjusted up to 30v. The 317 is a variable voltage regulator with adjustable 3terminal positivevoltage pins designed to supply more than 1.
Variable voltage power supply due friday, april, 2007 attachments. There is a high possibility of circuit damage if the dc power supply is not constant. My first variable power supply using lm317 eleccircuit. The lm317 is an adjustable threeterminal positivevoltage regulator capable of supplying more than 1. Scribd is the worlds largest social reading and publishing site. Having a variable regulated power supply that can output precise voltages in the 0 30volts interval is a great addon for any electronics lab. Variable dc power supply project report free download as word doc.
Variable dc power supply project report rectifier power supply. Variable voltage power supply instructional physics lab. In this article, i will discuss two methods of lm317 current boosting, using power pnp and npn pass transistors. For this weeks project i have built a 5 amp variable voltage regulator using an lm338 serial regulator. Lets make a high current power supply with lm317 voltage regulator which can supply upto 5 amp. To design the circuit for variable dc power supply that varies 2v. Building your own power supply is fun and using it throughout your constructional projects is the reward of your achievement.
This variable power supply is using 7805, 7809, 7812 or 7815 voltage regulators, where the last 2 digits. I have made this report file on the topic regulated power supply. Lm317 is one of the oldest, most used and wonderful linear voltage regulators. With the advent of chips or ics like lm317, l200, lm338, lm723, configuring power supply circuits with variable voltage output with the above exceptional qualities has become very easy nowadays. The maximum input voltage is 40 volts dc, and it will adjust down to 1. The other one i am using to create a portable power station for my desk. Regulated power supplyblock diagram,circuit diagram,working. It gives variable output dc voltage with change in value of r2. Variable power supply using lm317 voltage regulator. This ic normally generates voltages in the range of 1. It has a capacity to develop a reference voltage of 1.
It will deliver up to 600ma of current with current limiting. The output of ordinary dc power supply remains steady as long as ac mains voltage or load is contrast. Power supply project is an authentic record of my own work carried under the supervision of. This file is a detailed lab report for a variable power supply that will. The three terminals are input pin, output pin and adjustment pin. However make sure that all the 2n3055 are mounted over a large common heatsink, using a generous amount of heatsink compound paste but without mica isolators. The lm317t is the adjustable regulator ic, can adjust the output voltage of 1. This type of voltage regulators have output voltage in the range of 1. This project uses a transformer to step down the incoming ac.
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