3 ms·
Could it be that you inadvertently smoothed the visual flicker on the electrical side? Consider fast brightness sensor with known (ideally approximately linear)
by namibj 3y ago
Could it be that you inadvertently smoothed the visual flicker on the electrical side? Consider fast brightness sensor with known (ideally approximately linear) sensitivity to the AC component of brightness, and check with an oscilloscope or so. A soundcard with 96 kHz sample rate should probably have a high-enough filter cutoff to be quite and easily useful there, though I'd see to check the frequency response with an edge generator to confirm that it has linear sensitivity from low-ish frequencies to the >=10 kHz ones of particular interest.
- jcalvinowens 3y agoThat's a great point: above some frequency, the inductance of the system starts to average the voltage like the output of a switching power supply. I did think of that: I used a camera with a rolling shutter image sensor and manual exposure settings to prove to myself the LEDs were really still getting the full swing at higher frequencies. Also, to be clear, I'm talking about 12VDC COB LEDs with hard on/off PWM dimming, not A/C ripple. I don't know, but I'd expect the cutoff frequency to be a lot higher. The self inductance of 30ft of 16awg wire is about 20uH. I should test it...