LED Voltage Question

[Khimaros]

Hello all, just found this forum whilst searching for answers to a query I have. I'm building a 90's enterprise D with fibre optics and I've replaced the bulbs in that kit with LEDs. I've got some diffused white LEDs that I was going to use in the nacelles that are rated at 3-3.6v. I was planning on using a 12v circuit, and I'm not sure why they come with a voltage 'range'. My question is, can I use 4 of these in series (with the correct resistor of course)?

I've got some directional LEDs that are powering the fibre optics, but they came with a specific voltage of 3v. I don't have a breadboard or anything to test with, and i'm just a little concerned that these diffused LEDs will be getting the absolute minimum voltage they require and it won't be enough power.

[Joseph Osborn]

My question is, can I use 4 of these in series (with the correct resistor of course)?

Yes. But they might be a little bit brighter if you split them into two parallel series of two, and give each series its own resistor. Calculate your resistor value based on giving the LED's about 3.3 to 3.5 volts (de-rate them a little for insurance). You can also drop your incoming power down to 9 volts if you like, which means you can use smaller resistors all around. The last couple of models I've lit have run off 6 volts, and I find that's usually plenty of juice for even bright whites paired together.

There's no substitute for building the circuits and testing them against your own expectations, though.

[Khimaros]

You can also drop your incoming power down to 9 volts if you like, which means you can use smaller resistors all around. The last couple of models I've lit have run off 6 volts, and I find that's usually plenty of juice for even bright whites paired together.

There's no substitute for building the circuits and testing them against your own expectations, though.

Ok, that's what I was hoping. I just wanted to make sure I wasn't missing something obvious, it's a long time since I studied electronics in college. There's actually no reason for me to use 12v at all now, I had planned 12v because I had some 10cm cold cathodes I was going to use for the nacelles rated at 12v but these diffused LEDs give me more flexibility. It's back to the circuit drawing board for me...

I also found a breadboard on ebay for £5 so I'll just buy that and get experimenting! Thanks for your input!