Multi-function Transformer Based Variable Bench Power Supply Using LM317

In this tutorial we will show you how to make a Multi-function Transformer based Variable Bench Power Supply using LM317 . You can watch the video which is embedded in this step for construction, parts list, circuit diagram & testing or you can continue reading the post for the details

Banggood

• 1 * LM317 with Heat Sink - https://goo.gl/VxHfbW
• 1 * LM358 - https://goo.gl/uRDsus
• 6 * 1N4007 - https://goo.gl/51knVw
• 1 * IR Rx - https://goo.gl/h8ZNjm
• 1 * Pot Knob - https://goo.gl/cLs1CU
• 1 * Buzzer - https://goo.gl/Uufttq
• 1 * 8 Pin Socket - https://goo.gl/N1emWP
• 5 * 2 Pin Terminal Block - https://goo.gl/EbHE9a
• 1 * 3 Pin Terminal Block - https://goo.gl/8czSbM
• 1 * Voltmeter with ammeter - https://goo.gl/RD7VbF
• 2 Pair * Banana Connector male & female - https://goo.gl/pnKPXn
• 1 * LED
• 1 * BC548
• 1 * AC Cable
• 1 * 10K Trimmer
• Ceramic - 0.1uF
• 1 * 2 Way Switch
• 1 * 4.7K Pot with Knob
• Resistor - 2 * 120, 330, 470, 10K
• Electrolytic Cap - 10uF/50v , 470uF/50v
• 1 * 220v to 0-24v 1Amp Transformer

Amazon India

• LM317 - https://amzn.to/2LMOuW1
• LM358 - https://amzn.to/2kFpaF1
• BC548 - https://amzn.to/2LQ5Lxs
• 1N4007 - https://amzn.to/2sxrl0L
• Voltmeter with ammeter - https://amzn.to/2sxSoct

Amazon USA

• LM317 - https://amzn.to/2JmGegO
• LM358 - https://amzn.to/2L9MrKw
• BC548 - https://amzn.to/2J67MIg
• 1N4007 - https://amzn.to/2J7cmBZ
• Voltmeter with ammeter - https://amzn.to/2suxRW4

AliExpress

• LM317 - http://s.click.aliexpress.com/e/EmQnEi6
• LM358 - http://s.click.aliexpress.com/e/Rb6QFUR
• BC548 - http://s.click.aliexpress.com/e/neurnEQ
• 1N4007 - http://s.click.aliexpress.com/e/vjEqf2Z
• Voltmeter with ammeter - http://s.click.aliexpress.com/e/u7yjyZR

Refer the circuit diagram & construct your circuit on a PCB perf board or you can also order your PCB from an PCB fabricator. I order my PCB from JLCPCB. If you want to order the PCB you can download the Gerber File by Clicking Here . The Gerber file was created using KiCAD.

Please Note : The circuit diagram shared is for the meter which both Voltmeter & Ammeter in it. If you are using only a meter which has voltmeter then you need to connect the Pin1 of J5 to Pin2 of J5 & rest remains the same.

Working

For this bench power supply the IC used is LM317 which is a adjustable voltage regulator. LM317 provides a output voltage of 1.2v to 37v depending on the input supplied. For example if you supply 24v as input you will only be able get a output around 21v. In the circuit Diode D5 & D6 protects from short circuit. Diode D1, D2, D3 & D4 are arranged in a bridge rectifier configuration. Capacitor C1 & C2 are used has smoothing capacitor.
For connectivity & LED testing circuit BC548 transistor is used. And for the IR or Remote testing LM358 is used.

For the enclosure i am using a plastic box. Once you have a plastic box make all the holes necessary for inserting the external components like Voltmeter, IR LED, LED, Banana Connectors & wires.

Once the holes have been made connect the external components to the PCB board. The block diagram shared in this step is to be referred only if you are using the PCB board created by the Gerber file which shared by me in the previous step.

To use this as a power supply, slide the switch to center position & use the Voltmeter Knob to adjust the voltage & then you can connect it a bread board or any circuit you need

To perform a connectivity test, slide the switch to the connectivity position & then set the voltage between 5v to 9v using the Voltage knob & use the probes to test the connectivity. While testing if there is connection between two points then the Buzzer will Buzz.

To use this as an Remote tester first you need to adjust the sensitivity of the circuit using the Trimmer RV2. To adjust the sensitivity set the voltage to 6 volts & then keep pressing the button on remote while adjusting the sensitivity using the trimmer. You need to adjust until you get a blink on the LED. Once the sensitivity is set you can test any remote or IR LED

To use this as an LED tester follow the procedure of connectivity tester but set the voltage to 4volts or lesser

For testing results you can watch the video embedded in the post or Click Here

Thank you for reading
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