Designing 0-30V power supply using LM723

[zhi_yi]

Hi there, please help me, i tried to make a power supply using LM723 which its voltage "should" be adjustable from 0-30V/2A. I get the circuit schematic from internet, but after i make it on the breadboard, the results which i get is differ from what is says on the tutorial. I get 3V instead of 0V as the minimum voltage. please help me with a tutorial or a schematic that use LM723 and with voltage vary from 0 to 30V. Thank you

 

[IanP]

723 2n3055

To achieve voltages as low as 0V with 723 regulator you need to introduce small negative voltage reference ..
If you supply 723 of, say, -3V (regulated) and +35V (can be unregulated), the output can be controlled in the range you are after, that is from 0V to 30V ..

Here is one example ..
**broken link removed**
See how R1-D8 deliver additional negative (regulated) voltage ..

Regards,
IanP

 

[momename]

power supply 723

Regulator 0-30V 2A by IC 723 & 2N3055

**broken link removed**

Regulator 0-50V 2A by IC LM723 + Transistor 2N3055 & BD140 & A671

**broken link removed**