Dc power supply

it’s a circuit which simply take AC power as input and produce DC power as output.

1. khulna university of engineering & technology dept. of electronics & communication engineering course title :: Project lab Project supervisor :: - Mr. mehedi hasan Presenter :: Kazi Tanvir Isam (1409046) Farjana jahan nisa (1409047) Nowshin tasnim (1409048)

2. Dc power supply additional features :: Short Circuit Protection Over Voltage Protection Low Voltage protection

3. What & why dc power supply ? B asically it’s a circuit which simply take AC power as input and produce DC power as output. This device is like plug and play, all we need to do is just plug in to any AC source which is very much available in everywhere. And it is designed such a way that we can get desired voltage at output. In this era, our lifestyle is designed with so many electronics devices and most frequent used electronic devices are smartphone, tablet, laptop. To charge them we need the help of DC Power Supply. Even in amplifier and

4. Rectification circuit:: As you see this is our Rectification circuit and its operation is very simple . Here the step down transformer takes ~220v as input and generates around ~30v. The Bridge Rectifier which is combined with four diodes transform the AC current to DC. For more filtering we have also used a Capacitor.

5. Short circuit:: This is the circuit for Short Circuit. - This part is connected to a LM317 IC. Later we will show the full circuit diagram to make it clear. -In normal operation current passes through the LOAD and Green-LED turns ON. -Whenever the circuit is shorted the Green-LED goes OFF and RED turns ON. Generally this circuit works as a indicator of SHORT CIRCUIT.

6. Over & low voltage protection :: This is our circuit for over & low voltage protection. Here we have used two OP-AMP to control voltage. Two Zener Diodes to produce fixed voltage. And two LED for indication. The main operation will be discussed later along with the full Circuit Diagram .

7. Circuit diagram ::

8. Our limitations ::