Simple Variable Power Supply 1.5 – 30V, 5A

The power supply is based on two chips and in addition they contain only a few discrete components. In this regard, it is easy to manufacture and configuration. At the same time, the power supply provides a high level indicators, such as the smooth adjustment of the voltage in the large range, low coefficient of fluctuation, the output current up to 5A with the ability to stabilize the current, high reliability. Also, the power supply has short circuit protection.

The transformer uses the secondary winding of 25-35 volts and at a current of 5 A the output voltage is reduced not by much. Two capacitors connected in parallel 4700mkf provide a low ripple factor before the integral voltage regulator on the LM338. Potentiometer P1 can change the power supply from 1.5V to 25V. It is convenient to establish two potentiometers for coarse and consistently smooth adjustment of the tension. Double switch SW2 connects or disconnects a current executed on the chip LM317. Current regulator can limit the output current power supply in the range 0 … 1.5 A.

The potentiometer P2 is best to use the switch to 8-10 as a fixed value potentiometer is difficult to establish the desired current. The following table shows the approximate maximum value of the output current as a function of the resistor connected between pins and Out Adj chip LM317.

Current

Resistor

20 mA

62 Ohm

30 mA

43 Ohm

40 mA

33 Ohm

80 mA

16 Ohm

350 mA

3.9 Ohm

750 mA

1.8 Ohm

1000 mA

1.3 Ohm

Power supply current stabilization mode is useful for charging batteries up to 15AH.
The instrument used a voltmeter to 30V and the ammeter to 5A.
Both devices are equipped with a heatsink that tend to heat up, especially for large values ​​of output current, it is desirable to use thernal grease. Using a different heatsink and no contact with each other. Good Thermal ensure reliable operation. Boards, transformers and all the controls and displays are placed in a large case and has holes for air circulation.

Author: Andrey Veselov

psu

Share
Published by
psu

Recent Posts

Universal Battery Charger for Charging up to 18V Cell

This universal battery charger has regulated output voltage which can be adjusted as you need.…

5 years ago

Auto Switch-Off Power Supply (Variable Output 3.7V to 8.7V)

Here is the auto switch-off power supply which will turn off itself when there is…

6 years ago

High Voltage, Low Current Power Supply (2000VDC from 15VDC)

This is a high voltage, low current power supply capable to deliver 2000VDC output from…

6 years ago

15V 1A Regulated Symmetrical Power Supply

This is the easy built 15V 1A regulated symmetrical power supply capable to deliver stabilized…

7 years ago

12V / 3A Regulated Power Supply

Here we provide a powerful 12V / 3A regulated power supply circuit. Of course the…

7 years ago

How To Repair Computer Power Supply

If the power supply is damaged or does not work, the computer also will not…

7 years ago