I tried voltage regulator using LM338T.

It is okay to regulate the voltage but when I measured the output current it gives me around 1.5 amperes, not more than that. But datasheet specified it can output up to 7 amperes and 5 amperes continuously. I also tried with new LM338T but the result is the same.

Help me with this with a perfect circuit diagram and also I want to check whether my LM338 is dead.

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  • \$\begingroup\$ What do yo have the output voltage set to, and how are you adjusting the load? \$\endgroup\$ – Ron Beyer Feb 5 at 4:38
  • \$\begingroup\$ What are the voltages at the input and output of the LM338 when it is delivering 1.5 amps? \$\endgroup\$ – Peter Bennett Feb 5 at 5:06
  • \$\begingroup\$ In other words, how are you measuring the current? \$\endgroup\$ – User323693 Feb 5 at 5:09
  • \$\begingroup\$ Two questions for you: Can your powersupply deliver 7 amperes? How big is the heatsink you attached the LN338 to? \$\endgroup\$ – JRE Feb 5 at 7:01
  • \$\begingroup\$ I am using 17v 10 amp power supply. I measured the current through a 12v 120w motor, it consume 1 amp in no load when i applied load to the motor at max it only consume 1.5 amp but actually it demant 10 amp when rotor locked. Also i tried using 0.5 ohm 10 watt resistor the output but still the output current is 1.4 amp approximately. I use a heat sink of length 4.5 cm with two fins at edge of 3.5cm L and B with thickness 0.3cm. \$\endgroup\$ – akash Feb 5 at 7:45

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