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How do make a current adjust knob using LM723 for Linear Reg power supplies?

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message4guru

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Hi to all!!!

Currently I am trying to construct Laboratory type Linear Power Supply with LM723 IC. How do make a current limiting knob using LM723IC and my Specification Were 0-30V DC and 0-5A Current ? I want my power supply to have current control knob so that i can limit by current and save my series pass element from over heating or I could test my load. This is my intention. Please Help me in this Regard by small small example to make current adjustment in Linear regulated Power supply..

Thank you all....
 

I too saw the versatility of the 723 IC, and I wanted to make a similar project. (Adjustable voltage, adjustable current.) However it is difficult to combine the two functions simultaneously. They tend to 'fight' each other.

It is simple to set output voltage by a potentiometer adjustment. As for setting current, the current sensing resistor needs an adequate power rating because it carries the same current as your load. A potentiometer is unsuitable because it burns when you dial it to a low resistance so it carries high current.

I looked around for a schematic to do this type of project. I did not find one. I saw schematics for adjustable voltage or current, but not both from the same 723. I could be wrong.
 
A full range adjustable current-limit will require some additional external circuitry.
Is that acceptable?
 

The trick might be using a negative rail? That allows output to zero volts. Like this Elektor PSU (schematic)

The generic chinese red 0-30V 0-2A (or maybe 3A) power supply kits about $6 on eBay, so I caved in and use one.
Instead of a LM723, they use three op-amps. I dislike the -ve rail circuit and they have a safety to prevent full output if the rail is late or not working.
Can be modded for more current, adding pass transistor. Schematic is here too:
https://www.qsl.net/z33t/dc_0-30v_0-3A_eng.html
 

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Yes sir, I ready to spent on auxiliary circuit. Awaiting for your schematic circuit.
 

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