hi, guys, does anyone know how high should PWM frequency be in order not to see it?
High! ;)
thanks, Chibi, for thoroughly elaborated and constructive answer…now i see it more clearly…(…PWM…) :bigsmile:
I'm Sure above 2000 it's not easily detected by the eye, but I guess it really depends on the person.
I guess 1000 could be enough!
As a reference, the old fluorescent lamps used 100 or 120 hz frequency and for most people this is enough when looking at stationery things, but flicker can usual be detected out of the corner of the eye.
With moving things a higher frequency is needed, how much higher depends on a lot of factors. A led works like a strobe light and can freeze or slow movement if the frequency match (or nearly match) the repetition rate or a fraction or multiple of it.
2kHz and above, but that’s me. New poll maybe?
Fluorescent lamps like the T12, T8 make me feel sick. It is not even that I can see the flickering. I cannot tolerate them for long.
i’m asking because of the Maxtoch 21 that was on the group buy…it says 4Khz med and low…i wonder if someone can say something about it…
4khz
I cannot stand noticeable PWM. 1kHz is still kind of noticeable. But 4kHz should be good enough.
The answer is: constant current
8000+
4k should be more then enough.
My custom SRK driver uses 15,000 Hz…
I have an LED strip with a PWM dimmer in my kitchen around the kitchen sink. It runs at 150 Hz and normally I cannot see it. But it does weird things when the water is running. Sort of gives a stop-motion effect. Kinda interesting actually.
In PWM dimmers or faders I have built I try to keep it around 250 to 500 Hz. I've never seen PWM effects in that range, though if there is really fast moving things in view it might be noticeable. One of the reasons I keep it in this range is to reduce heat in the MOSFET that is controlling the load current. Most of the heat in a MOSFET occurs during the transition from off to on and back. The frequency might make the difference between requiring a heat sink or not.
Exactly, unnecessarily high pwm just wastes energy.
2kHz it usually what I set it at. It’s only slightly noticeable when the light is pointed at reflective objects.