Last Updated on March 16, 2024
Simple Voltage Regulator Circuit designed by using IC LM723 From Texas Instruments. LM723 is an integrated series regulator whose output voltage can be adjusted between 2V and 37 Volts. This IC by itself can deliver an output current of 150mA and the maximum input voltage of this IC is 40V.
As stated in the Datasheet IC LM723 Can deliver 150mA output current without External pass transistor and it can deliver 10A output current by adding proper external transistors. The LM723/LM723C is also useful in a wide range of other applications such as a shunt regulator, a current regulator or a temperature controller.
Circuit Diagram
BOM
| S NO | DESIGNATOR | VALUE | QUANTITY |
| 1 | TRANSFORMER T1 | 230V | 1 |
| 2 | D1 | 2W10 | 1 |
| 3 | C1 | 1000F | 1 |
| C2 | 100nF | 1 | |
| C3 | 470F | 1 | |
| C4 | 100nF | 1 | |
| C5 | 100F | 1 | |
| 4 | RV1 | 10K | 1 |
| R2 | 680 | 1 | |
| R3 | 82K | 1 | |
| R4 | 1K | 1 | |
| R5 | 0.18 /5W | 1 | |
| R6 | 8.2K | 1 | |
| R7 | 2.2K | 1 | |
| 5 | D2,D3 | 6A6 | 1 |
| 6 | U1 | LM 723_DIP14 | 1 |
| 7 | Q1 | MJ3001 | 1 |
Construction and Working
Here the T1 can be a 230V primary ,25V secondary, 5A step down transformer. Rectified DC supply from bridge rectifier with the help of C1,C2 capacitor. The Dc supply applied to the V ,Vc pins. Vref pin is connected to the Non-inverting pin and ground through RV1,R2 resistors. By changing value of RV1 we can change the output voltage levels at Vout pin.
Here 3A output current is attained by adding a pass transistor (Q1) to the ICs output. The pass transistor used here is a NPN darlington transistor MJ3001. The pass transistor connected at the output for current control. Schottky barrier diode D2,D3 are used for reverse protection.
Frequency compensation (FC) used to connect capacitor which high frequency noises. Here inverting pin and FC pin connected between R6,R7 resistor for to take output voltage sample and frequency compensation. Adjustable Vout Dc supply is connected to the output terminal.
Reference
IC LM723 Datasheet from Texas Instruments
Note:-
This Circuit involves in handling of High Voltage AC Supply. Handle with extreme care.