When discussing variable wattage/voltage devices I've seen more than a few people mention "mod xxx doesn't use PWM so it hit smoother" or "mod xxx uses PWM so it's harsh"
There still seems to be some confusion as to what PWM means so I figured I'd make a quick note:
All variable wattage/voltage devices use pulse width modulation. PWM is just the technique used to control the voltage by taking a higher voltage (either from dual cells or from a boost circuit) and pulsing it so that the effective output voltage is lower. The only other way to down-regulate voltage in these devices is to use a linear voltage regulator (basically a variable resistor) which controls the voltage by converting the extra energy into heat. There might be a few old home-made devices that use linear voltage regulators, but everything on the market today uses PWM.
The difference in devices comes from two main factors: the frequency of the switching and the way the chip determines voltage.
Higher frequency devices pulse fast enough that the output signal is basically a flat DC signal, cheap chips have a frequency low enough that the output signal is choppy and the vape a bit harsh. Regardless of what voltage you set the device to, a lower frequency device will always be a bit harsher/hotter compared to a DC output.
The way the chip determines voltage, whether it be RMS or Avg, will also determine how the device performs. RMS is more accurate in producing a given voltage, so if you have a device set to/using RMS at 4 volts it will closely match an actual 4VDC. Using average the voltage is less accurate, so if you set your device to 4 volts it might not closely match an actual 4VDC but it's just an issue of scale. Meaning if your device is set at 4v, it might actually match 4.3VDC so all you have to do is adjust your setting to get a vape the same as vaping off a DC source (as long as the device uses high frequency PWM)
Hopefully this clears things up a bit, and if anyone notices any errors in what I've presented please let me know!
There still seems to be some confusion as to what PWM means so I figured I'd make a quick note:
All variable wattage/voltage devices use pulse width modulation. PWM is just the technique used to control the voltage by taking a higher voltage (either from dual cells or from a boost circuit) and pulsing it so that the effective output voltage is lower. The only other way to down-regulate voltage in these devices is to use a linear voltage regulator (basically a variable resistor) which controls the voltage by converting the extra energy into heat. There might be a few old home-made devices that use linear voltage regulators, but everything on the market today uses PWM.
The difference in devices comes from two main factors: the frequency of the switching and the way the chip determines voltage.
Higher frequency devices pulse fast enough that the output signal is basically a flat DC signal, cheap chips have a frequency low enough that the output signal is choppy and the vape a bit harsh. Regardless of what voltage you set the device to, a lower frequency device will always be a bit harsher/hotter compared to a DC output.
The way the chip determines voltage, whether it be RMS or Avg, will also determine how the device performs. RMS is more accurate in producing a given voltage, so if you have a device set to/using RMS at 4 volts it will closely match an actual 4VDC. Using average the voltage is less accurate, so if you set your device to 4 volts it might not closely match an actual 4VDC but it's just an issue of scale. Meaning if your device is set at 4v, it might actually match 4.3VDC so all you have to do is adjust your setting to get a vape the same as vaping off a DC source (as long as the device uses high frequency PWM)
Hopefully this clears things up a bit, and if anyone notices any errors in what I've presented please let me know!
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