transformers

[thershow1]

Hi all
Just after some advice on wiring a 240v to 12v tranny. I'm intending to wire 2 small leds off of my existing bathroom spotlights.
The transformer has + and - and output and an L and N input.
The leds have 4 wires red,black,blue and green they are color changing but am not requiring this function
Any help much appreciated
Thanks

 

[bernardgreen]

These colour changing LEDs will require a matching colour changing driver.

You cannot simply apply 12 volts to the LEDs. It won't work.

 

[thershow1]

Apparently according to the company i can but i have lost their instructions on how to and need to get this sorted by the end of today

 

[winston1]

The transformer has + and - and output and an L and N input.

It is not a transformer then. A transformer is a wire wound device that only has an AC output.

 

[ericmark]

We normally call something with + and - a power supply rather than transformer although clearly it transforms it from 230vac to 12vdc so the name be it transformer, driver or power supply is really not important.

Again LED's typically have around a 1.2 to 2 volt supply and are really a current device rather than voltage so require some form of control be it a simple resistor or a complex inverter.

So a 12 volt LED will include some form of control built in. The problem is we don't know what that control is so no idea to is AC or DC or what needs connecting.

So sorry you need to find out what the LED's you have need there is no one size fits all answer.

 

[Robin0577]

LED units normally come in two flavours, those designed for constant voltage drive and those designed for constant current drive. Constant voltage units have some form of current limiting built in and will work from a standard power supply, whereas constant current types require a specialist driver.

DISCLAIMER - WHAT FOLLOWS IS EDUCATED GUESSWORK ONLY!


IF, the manufacturer has stated that the LEDs are suitable to be directly driven from a 12v source, then they are likely configured for constant voltage drive at 12v

Typically in the case of a multicolour unit, you will have red green and blue LEDs inside, all three of which will be needed to make "white" light. Convention has it that the black wire will be the common return and the other 3 will be red, green and blue supplies BUT it could be common anode (+) or common cathode (-) connected. Usually LEDs will simply not work if connected with the wrong polarity but there are some types that can be damaged, it would be safer to use a meter with a diode test function first to determine the correct polarity...