I have 24 VDC input supply and I want to drive a LED bulb that runs from a 12V AC/DC supply. I am trying to find out a value of resistor that I can use. I found out the resistance of LED bulb by measuring voltage & current (11.34V/0.51A = 22.23 OHM).
GOAL: GET A CORRECT RESISTOR TO GET 12V AT BULB PINS
Now, I tried few Vishay aluminum power resistors and got following values (see attached file) (mr16 led BULB rated for 5W - datasheet attached, 12V AC/DC, this bulb can accept 12V AC/DC & has a rectifier to convert to 12VDC if AC is supplied):
I tried a 12V, 5W halogen bulb too, I measured 13.13V at bulb pins (why the difference in this value?). For whatever reason, I cannot get 12V, am I doing anything wrong? Do I have to use exact 22.23 ohms?
Second question: the one I am trying has a Aluminum heatsink on it, even the 25W resistor gets hot. If I use a 50W, will it produce less heat because of bigger heatsink? Thanks. Any help is appreciated.
Mayur
GOAL: GET A CORRECT RESISTOR TO GET 12V AT BULB PINS
Now, I tried few Vishay aluminum power resistors and got following values (see attached file) (mr16 led BULB rated for 5W - datasheet attached, 12V AC/DC, this bulb can accept 12V AC/DC & has a rectifier to convert to 12VDC if AC is supplied):
I tried a 12V, 5W halogen bulb too, I measured 13.13V at bulb pins (why the difference in this value?). For whatever reason, I cannot get 12V, am I doing anything wrong? Do I have to use exact 22.23 ohms?
Second question: the one I am trying has a Aluminum heatsink on it, even the 25W resistor gets hot. If I use a 50W, will it produce less heat because of bigger heatsink? Thanks. Any help is appreciated.
Mayur
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