I've checked also new (bloody because of two those cheeap one basicly shorted home grid 230VAC mains
) electronic fluorescent light bulbs like in attachment and its light looks very random when detected with LDR, but didn't made Fourier analysis yet to see its spectrum.
Anyway, I believe those even small pulses of light intensity can be very bad for our sight and now investigate this, so this why I'm interested in cheap methods to stabilize this 230VAC current, provide constant current to such light bulbs (I mean classic old light bulb, because of not sure if those new fluorescent can be powered with 230V(DC)) and compare room full of such AC and DC lights and see how human reacts to such light sources, because of I feel alittle bit tired in this artifical light and this might be this flickering, I guess.
Of course LED lamps are an option, but still we need ensure if they have this current constant, while many cheap ones do not have when looked inside its circuit-they have only current limiting capacitors, etc. so for sure its output is flickering
So, made this small LDR probe to be able even in the shop check if such light sources have current stabilized and there is no flickering
Can put this inside laptop microphone input and no need to carry huge scope to prove in the shop that their LED 230VAC light bulbs are bullshit