0-30V/0-7A power supply unit with LM723 and Arduino volt and ampermeter


Nicu Florica has been working on a power supply project, inspired by Albasete’s power supply unit with LM723 and Arduino volt and ampermeter:

It use an Arduino nano board with i2c LCD1602 display, a active buzzer for indicate shortcircuit case. Also, I put DS18B20 temperature sensor and relay for power a cooler when tenmperature is bigger than a threshold level.
For albasete version, I write psu_reber_ver3ro.ino sketch. In this sketch I put value for albasete case (R1 = 1k put between GND and A1 port, R2 = 39k put between +OUT and A1) and value for threshold (temax) and hysteresis value

See the full post and more details on his blog, Arduinotehniq.

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  1. This is of course no “0-30V” supply – the single-supply standard LM723 schematic can’t go all the way down to zero, which is why I could never see these as “proper” bench supplies. The original sources quoted readily acknowledge this, calling it a more truthful “1-27V” supply. The whole thing is even more amusing given there’s a second transformer used anyway, just to power the Arduino, which could have helped pull the reference ground below zero, resulting in a true “down to 0V” supply.

  2. So Romanians use old ICs too, a bit reminiscent of Dilshan’s projects.
    I’m vaguely disappointed by the liberal use of float data and float calculations. Young ‘uns these days have it so easy… and a I2C LCD display too, very luxurious compared to the old days.
    One thing, if I built a project like that, I would be irresistibly curious about the accuracy of V and I, especially that large block of 4 R in parallel, and would insist on calibration.

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