I am attempting to install two lights to illuminate my American Flag. I want to use LEDs instead of incandescent bulbs. The power source for my lights is the 18VAC transformer that powers my house number. It has two automotive style incandescent bulbs. I chose this because of its proximity to the flag. I put together the circuit shown as Circuit 1 and it seems to work fine. The problem is that it's kind of dim. So I have purchased some 3W and 5W LEDs from Vollong. Circuits 2 and 3 are my ideas for wiring these devices. My concern is the power dissipation required for the current limiting resistor.
I have also considered rectifying the AC and then using a constant current source like an LM317 but space is an issue and due to the voltage drop of the LM317 I probably couldn't drive the 5W device (with it's 7V Vf). So I am hoping that a simpler solution is possible.
I have also considered rectifying the AC and then using a constant current source like an LM317 but space is an issue and due to the voltage drop of the LM317 I probably couldn't drive the 5W device (with it's 7V Vf). So I am hoping that a simpler solution is possible.
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