any rule of thumb

[jerseyman32]

This maybe a silly question but is there a rule of thumb to figure out wheter a mod runs at mean or rms, ive noticed some of them dont say in the product descriptions

 

[Smann245]

Mean and rms doesnt apply to a flat dc signal. The better devices have gotten away from pwm and output a pretty flat and clean dc signal, so mean or rms doesnt apply.

 

[classwife]

Moved to Variable Voltage APV Discussion from APV Discussion

 

[DaveP]

Mean (average) or RMS is simply a calculation used to approximate the actual voltage value of a synthesized DC output. The difference is in the way that the waveform is measured. Waveforms can be triangular, square, or sinusoidal. All can have varying on and off times based on shape, frequency, wavelength, and amplitude. Any of those can change the apparent voltage as seen by a voltmeter.

http://www.learnabout-electronics.org/ac_theory/ac_waves02.php

A variable mod has to use (PWM) pulse wave modulation to achieve variable output. Higher switching frequencies equate to closer approximations of actual DC output, but only a mech can produce true DC output.

There's ripple in the output of any variable mod. It's the frequency of the waveform that determines how close it is to actual DC. There are 33hz, 66hz, and 800hz implementations in different mods. Provari runs at 800hz. Most Chinese mods are in the lower ranges, but they are improving. The higher the PWM frequency the closer it comes to approximating DC output. If it sounds like a rattlesnake, it's low frequency. If it sounds like a smooth boiling noise, it's higher.

This blog by Baditude is definitely slanted toward the Provari, but it explains why high PWM frequencies produce smoother vapes.
http://www.e-cigarette-forum.com/forum/blogs/baditude/5569-13-why-provari-page2.html

 

[DaveP]

Mean and rms doesnt apply to a flat dc signal. The better devices have gotten away from pwm and output a pretty flat and clean dc signal, so mean or rms doesnt apply.

Voltage output has become cleaner in the newer and mostly the higher priced mods. They still use switched mode power supplies, but the frequencies have become higher and even on a scope some are beginning to look very smooth until you expand the view.

 

[dimo]

I think the istick 20W is the only mod these days that uses mean. All the rest use RMS if they do PWM. Ones that have dc-dc converters don't apply. They provide an essentially flat signal.