YADTMI - yet another dual triode mixing idea

[SoulFetish]

Linear in respect of what? Light emission vs current or current vs voltage?
.

Current vs Voltage. The on resistance is very low and I would suspect it to clamp the voltage around 1.5V, and not increase much more than a 100mV or so.

fairchild red 5mm led mv50152 datasheet.pdf

[Helmholtz]

Current vs Voltage.

I can't imagine an LED (or other diode) being linear around the transition between very low and higher currents, i.e. around the threshold voltage. This non-linearity will introduce some distortion but hopefully only at a g2 current level where the signal would get distorted anyway.

Current vs voltage linearity above the threshold voltage doesn't matter as the LED will (hopefully ) light and indicate overload.

[SoulFetish]

I can't imagine an LED (or other diode) being linear around the transition between very low and higher currents, i.e. around the threshold voltage. This non-linearity will introduce some distortion but hopefully only at a g2 current level where the signal would get distorted anyway.

Current vs voltage linearity above the threshold voltage doesn't matter as the LED will (hopefully ) light and indicate overload.

Right, looking at the graph, that’s the area of it’s most drastic curve.

[Helmholtz]

Right, looking at the graph, that’s the area of it’s most drastic curve.

Sure, I just wondered why you stressed the "extreme" linearity.