LM317 and LM338 are easy to use and pretty straightforward devices for voltage regulation. LM338 is said to be able to supply 5A and LM317 more than 1A current.
Just as an experiment I built two regulators, one with 317 and the other with 338. I used 220 ohms / 680 ohms which gave me an output voltage of about 5.8 Volts. So far so good...
As I connected the output to my current load device, I noticed that both devices dropped the output voltage under 3 V at just 1A output!!!
I have tried with two separate LM317's and 4 LM338's with the same result.
I didn't use a breadboard nor a PCB. I mounted the IC on a small heatsink and soldered the two resistors and the capacitors (which are not mandatory as far as I know) directly at the pins. My wires were 22 AWG RC aircraft servo wires (they can handle more than 5 A without any problems).
As power source I used a lab power supply which is capable of providing 10 A. As input voltage I have set 9 V for the regulator (pretty sufficient for 5.8 V output).
Is there an explanation for this unexpected behaviour oh these voltage regulator IC's? (other than they all are defective / counterfeit products).
Just as an experiment I built two regulators, one with 317 and the other with 338. I used 220 ohms / 680 ohms which gave me an output voltage of about 5.8 Volts. So far so good...
As I connected the output to my current load device, I noticed that both devices dropped the output voltage under 3 V at just 1A output!!!
I have tried with two separate LM317's and 4 LM338's with the same result.
I didn't use a breadboard nor a PCB. I mounted the IC on a small heatsink and soldered the two resistors and the capacitors (which are not mandatory as far as I know) directly at the pins. My wires were 22 AWG RC aircraft servo wires (they can handle more than 5 A without any problems).
As power source I used a lab power supply which is capable of providing 10 A. As input voltage I have set 9 V for the regulator (pretty sufficient for 5.8 V output).
Is there an explanation for this unexpected behaviour oh these voltage regulator IC's? (other than they all are defective / counterfeit products).