PWM Alters Light Meter Readings

[jayflash]

Hopefully, this is the correct forum for this subject.

I've noticed that my metering set-up lacks the persistence of my vision. When comparing similar light intensities between current limited and PWM driven lights, the PWM units indicates about half the meter reading for the same intensity. This is, probably, well known to our experienced testers, but I, only recently, noticed this effect.

 

[SafetyBob]

Most likely because the electronics of the meter are seeing the actual pulsing (turning on and off) of the PWM and reporting it factually versus the constant shining (illumination) of the current limiting device.

Thats the neat thing I love about PWM, your eyes can't tell that it is turning on and off....it just appears to be dimming.

Bob E.

 

[SilverFox]

Hello Jayflash,

Do you notice similar behavior when you use the peak hold function?

Tom

 

[jayflash]

Great idea, Tom, I'll swap meters to one with that function and try it. I'd imagine the pulse rate will affect meter readings, also.