How to measure 120 Hz ripple current at the output of an LED driver?
"Ripple current &lt;2% at 120Hz" means the power supply has decent regulation with input line induced load ripple from line bridge input to DC-DC converter that would not be visible. No need to measure it unless you need to verify the spec.

If you used any reverse biased photo diode (PD) the voltage into a load R will show 2% FS ripple on the current with all other light sources turned off driven by 60Hz or blocked radiance to PD.







simulate this circuit &ndash; Schematic created using CircuitLab

If you don't have a PD, use any clear LED.