Hi folks, plea for help.
I've wired my daughter's LED fairy lights to a USB-2 supply, but now they're much brighter than the 3 AA batteries made them (and we quite preferred when the batteries were half flat), so I've been trying to find a variable resistor to put in series to reduce the intensity.
I bought a one on eBay before I did the sums suggesting I needed something around 1Ω (5V-4.5V=0.5V, 0.5A, 0.25W) so what I got is 37Ω-1kΩ and 0.2W, so I know I'm going to have to buy something smaller, but even if the new one is rated for 0.25W, I'm worried about putting it in the plastic battery case the LEDs came with - will it overheat or something? Should I buy for more than my rated wattage?
I looked for fixed resistance 1Ω 0.5W resistors on eBay, thinking I could just put them in series and/or parallel to adjust things permanently, and forget variable dinning, but now I'm doubting my calculations and assumptions - do I need 10Ω instead? I only have one AA battery's space in the case, because I'm using two batteries to wedge the usb power leads in place.
Any help would be very welcome!
I've wired my daughter's LED fairy lights to a USB-2 supply, but now they're much brighter than the 3 AA batteries made them (and we quite preferred when the batteries were half flat), so I've been trying to find a variable resistor to put in series to reduce the intensity.
I bought a one on eBay before I did the sums suggesting I needed something around 1Ω (5V-4.5V=0.5V, 0.5A, 0.25W) so what I got is 37Ω-1kΩ and 0.2W, so I know I'm going to have to buy something smaller, but even if the new one is rated for 0.25W, I'm worried about putting it in the plastic battery case the LEDs came with - will it overheat or something? Should I buy for more than my rated wattage?
I looked for fixed resistance 1Ω 0.5W resistors on eBay, thinking I could just put them in series and/or parallel to adjust things permanently, and forget variable dinning, but now I'm doubting my calculations and assumptions - do I need 10Ω instead? I only have one AA battery's space in the case, because I'm using two batteries to wedge the usb power leads in place.
Any help would be very welcome!