Custom Circuit (LED Ring Light) Requirements

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Originally Posted by SuperBK

Have you considered hooking it to a Spike instead of building your own circuit?

Yes but a spike relay costs $35 + extra weight and a transistor costs about $1.50. This is a low current application.
The concern with transistor is back-current from a load after power-off, so in my experience with integrated circuits we always need to add a diode to prevent said back current. In this case, the LEDs would serve its own purpose I'd think, but I just wasn't sure how inspectors treat custom circuits.