POWER SUPPLY BY USING LM317

POWER SUPPLY BY USING LM317

Introduction:

We have made 30 Volt 5 Amp regulated power supply. It can be used to charge different types of batteries and home appliances.

Circuit Diagram of Variable Voltage Regulated Power Supply:

Working:

1. Steps involved in making a Power Supply :

·         Transformer

·         Rectifier

·         Filtering

·         Regulator

2. A step-down transformer is used to reduce the dangerously high voltage to a safer level.
3. Bride Rectifier, Converts the AC voltage to DC, available in the form of packages of combination of four diodes forming a bridge. Bridge Rectifier output is obtained from the (+) and (-) marked terminals.
4. Filtering is technique in which a pure DC is obtained. The output of a bridge rectifier is not a pure DC and needs to be converted into pure form.A capacitive circuit is used as a filter or a smoother it converts the pulsating DC into a pure DC with a little ripples.
5. Regulator eliminates ripple by setting DC output to a fixed voltage. Voltage regulator ICs are available with fixed( typically 5,12 and 15V ) or variable output voltages. We used LM 317.
6. The output is shown through Digital volt meter & Analog Ampere meter.

Components used in the circuit listed below:

• One 3×5" perf-board
• LM317 variable voltage regulator
• BR805D Bridge Rectifier
• 120 VAC to 24 VDC transformer
• Power cable
• One 2200 microfarad capacitors
• One 0.1 microfarad capacitor
• One 100 ohm resistor
• One 5k ohm variable resistor

CONCLUSION:

The power supply is used to convert  AC voltage to DC voltage for suitable appliances . The LM 371 variable voltage regulator is used for desired output and the final DC output is not a straight line but a small ripple line.

working circuit. checked !