Topic: LED Lighting.

[KarlG]

I bought a couple of circular 2" Ø LED lamps from the local supermarket with the intention of using them for stop lamps. Nothing strange about that, but it's strange that it doesn't matter which way I connect them to the battery they illuminate.

You read everywhere that LED bulbs are polarity conscious, so can anyone explain how these lamps work? No I'm not using an AC battery.

[jockywilson11]

Must have a rectifier built in :-)

[KarlG]

I've found some information in the IN, it appears they maybe  inverse parallel LEDs designed for 12v AC use. That is, the anode from one is connected the the cathode of the other, and the cathode to the anode of the other. This way it doesn't matter which way you connect them with a DC supply , but are more efficient with AC use as only 50% of the diode construction is being used in DC operation.

[jockywilson11]

Ah they must be for Motorcycle use then. A lot of the old style vespas and lambrettas had AC systems, ( PX125s and LML Stars still do), so it would make sense to basically make a bridge rectifier out of the LEDs for that sort application.

[KarlG]

Hi,

no, they were made for home use e.g. bathroom, kitchen, etc. They are encased in a ceramic housing.

I've had the thing apart and there are no additional components.