RMS and MEAN

Variable voltage devices with Chinese origins often have a menu option that allows the user to switch between RMS and MEAN (or AVG) options.  Which should you choose, and why?  I’m no electrical engineer, so I can really only give you an overview of the engineering involved.  What I can tell you is that RMS should be your choice.

Let’s start with the an explanation of why the RMS/Mean option is included in the first place.  Many variable voltage devices use pulse width modulation (PWM) circuitry to deliver power.  That’s how we can get a 6 volt output from a 3.7volt battery.  The power essentially goes on and off rapidly and looks like a wave on an oscilloscope.

The VMAX and early versions of the ZMAX used this pulse width modulation, but used MEAN or AVG to measure and adjust the output.  Because this method does not take into account the “off” time in PWM, the actual power output was often much higher than what the device was set to.  You can set a VMAX to 4 volts and get output closer to 5 volts.  It’s a great way to burn a cartomizer if you’re not careful.

Later versions of the ZMAX have been referred to as having the “8th menu option,” which signifies the ability to switch the device between RMS and Mean.  RMS measures the output much more accurately and will provide a much more consistent vape.  Quite frankly, there is no reason to switch back to MEAN and it’s curious why that would even be included as an option.  It’s like giving a driver a choice of an accurate speedometer or one that reads 10mph too low.

So the short answer is that RMS is the easy choice.  The question really is why were we given that choice in the first place?

Comments are closed.