jellyfish lights SOLVED

want to use led lights 5mm in series to light art jellyfish using battery box 2aa or 4aa and resistor and switch etc etc can anyone help a novice

by steamer
September 24, 2017

1 Answer

Answer by mikerogerswsm

Each light drops about 2 volts (3 volts if white) so series connection could add up too much. I would put them in parallel, with a series resistor to limit the current. Each led requires about 20 mA, so one led run off 4aa (6V) would need about 200 ohms. Greater numbers of leds will require proportionately lower values of resistor, for example ten leds would need about 20 ohms. The resistor power rating should be greater than 0.12 W per led, 1.2 W for ten leds. Your 2aa is insufficient, 4aa is overkill, I use 3 x d-cell. Then the resistor is about 125 ohms for one led or 12.5 ohms more than 0.5 W for ten leds. AA cells don't last more than a couple of days. C cells last up to a week. Use alkaline cells, the most cost-effective are Poundland Kodaks. Here are some photos of my lash-up:

ACCEPTED +1 vote
by mikerogerswsm
September 30, 2017

ps - here are some photos:

by mikerogerswsm
September 25, 2017

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