LED circuit

[jpeg666]

I am creating a small grow light for plants

Okay Hopefully there is someone in here that can help me. I have 6 super bright (blinding) 3 watt red bridgelux LEDs I want to have them as supplemental lighting around the foliage to my current Fluorescent lighting.

I have a wall plug transformer that outputs 12v AC at 1 Amp I need help building a circuit to power these leds. I know I need to rectify the AC current to DC current and I need help with that too.

If anyone can help me with making the circuit I would be very grateful.

as for the 12V AC doesn't that mean I have 16.96 Peak voltage? Because the 12V is the RMS and the 16.96V is the actual voltage?

 

[Alchymist]

I am creating a small grow light for plants

Okay Hopefully there is someone in here that can help me. I have 6 super bright (blinding) 3 watt red bridgelux LEDs I want to have them as supplemental lighting around the foliage to my current Fluorescent lighting.

I have a wall plug transformer that outputs 12v AC at 1 Amp I need help building a circuit to power these leds. I know I need to rectify the AC current to DC current and I need help with that too.

If anyone can help me with making the circuit I would be very grateful.

as for the 12V AC doesn't that mean I have 16.96 Peak voltage? Because the 12V is the RMS and the 16.96V is the actual voltage?

12 volts ac is an rms value which is equivalent to 12 volts dc power wise. While a power supply (unregulated) made of diodes and capacitors will reach a higher voltage unloaded, when loaded the voltage will drop until as the load increases to maximum the voltage will bottom out at 12 vdc. Regulated power supplies use various methods to counteract the no load to full load variations.

Designing a power supply for your leds start with the spec sheet for the leds - Ifwd,, rated voltage, etc.

 

[(*steve*)]

The best solution is to rectify and filter (a little) the AC and use a constant current driver for the LEDs.

You have enough overhead that you can probably connect a bridge rectifier, an use an LM317 or similar set up as a constant current source.

12VAC means 12V RMS AC. Yes your peak voltage is something like what you say, but that doesn't mean it's the "real voltage"

If you draw 1A from this power supply after rectification and filtering you will be overloading it. I would recommend no more than 700 mA.

 

[jpeg666]

okay that is all helpful but I am asking for someone to help me do what you are proposing. Like draw a schematic or throw out part names. so i know what to buy and where to sodler the parts.

http://www.ebay.com/itm/Constant-Cu...123?pt=LH_DefaultDomain_0&hash=item1c2266ddf3

something like this work??

 

[(*steve*)]

Perhaps the easiest is something like this:

http://www.ebay.com/itm/Cree-Q5-LED...872?pt=LH_DefaultDomain_0&hash=item2a10ac4d50

edit: you still need to rectify and filter the 12VAC you have.

For that, a 40V 1A (or higher) bridge rectifier and a 1000uF 25V capacitor would be the go.