How can I piggy back a parallel circuit without sucking up amperage?
First of all, you can’t put LEDs in parallel, as they are current driven devices. they all have different Vf, forward voltage drops, and the lowest one will take all of the current, unless they are very well matched. Perhaps you could use an op-amp or other circuit to measure the voltage across the LED and replicate that in your circuit. A simple voltage follower would do that. BUT, as I said, replicating the voltage says nothing about the brightness of a LED. A given voltage could, for one LED, cause it not even to glow, and for another , cause it to be so bright it burned out. Current is better, as it will cause a group of LEDs to produce about the same amount of light, as long as they are the same type. But you have to interrupt the circuit to sense the current. And different types of LED produce different amount of light for the same current. sorry, don’t see how this could work. Unless you got very complicated and put a computer in the loop. Sense the current in the LED, and based
