PWM - acronym definition request

[Tom Cloud]

>While looking through some old posts, I came across the acronym PWM in
>association with turbo control.  I suspect it is an inline valve in the
>wastegate vacuum control line.  But can't figure it out on my own.
>
>What does the PWM acronym stand for?

dunno about with turbo control, but PWM means "pulse width modulation"
in the eclectic world ....  see, there's three common ways of regulating
how much energy is dumped out of a power source (envision controlling
wawa outta a dam)

 - you can do the linear regulator thing -- as in series or shunt
regulators.  Problem with this is they get hot and dissipate lots of
heat.  Good thing about them is they don't make lotsa noise that
screws up theyselves and other things (this is analogous to opening
the floodgates a little to get the desired flow)

then, there's the "switching" approach -- i.e. "pulse" the gates
full open and then closed to achieve an average flow equal to what you
want.  Two ways that's typically done:

 - have a fixed time you hold the gate open and control how often you
open it (constant pulse width, variable frequency)

 - have a fixed, repetitive opening time and control how long the gate
is left open -- this is PWM.  The pulse occurs at a fixed PRR (pulse
repetition rate) or frequency and the width of the pulse is varied
(constant frequency, variable pulse width).


The PWM is the most common, in my experience ... and I can't remember
what the other is called (if I ever knew)  8-)


Tom Cloud

     Madness takes its toll   .....   please have exact change