I'm trying to vary the voltage (6v - 10v) on several leds (about 13 watts). I've used an LM338T with 150 ohm R1 and a 5K linear pot R2. The power supply is 12vdc 5 amp.
Under no load the regulator does exactly as I want (0v - to 10.5v), however when I connect the load the max voltage drops to about 5.5v. No heat generated, chip is cool and resistors are cool.
Page 13 of this data sheet. Just remember that R1 in the drawing is going to be a low value high wattage resistor, you can't use a small .5 watt pot if you plan to draw much current.
I'm trying to vary the voltage (6v - 10v) on several leds (about 13 watts). I've used an LM338T with 150 ohm R1 and a 5K linear pot R2. The power supply is 12vdc 5 amp.
Under no load the regulator does exactly as I want (0v - to 10.5v), however when I connect the load the max voltage drops to about 5.5v. No heat generated, chip is cool and resistors are cool.
Sir, kindly post the schematic of your design so I can also learn the application of LM338T. I'm just a newbie who wants to bridge the gap between theories they teach in school and application. Thank you.