Thank you for your help

[Krister Wikstrom]

-----Original Message-----
Date: Thursday, November 13, 1997 17:47
Subject: Thank you for your help


>A couple of week ago I posted a message asking suggestions to make a 5v
>power supply for the car (12-14volts input, 5 volts ouput) and not
>having the problem of dissipating 7W.


One thing that I have also learned (most aspects from comments on this list,
thanks),
is to protect the PSU from voltage spikes. There can be voltage spikes of
several
hundred volts in a car, and according to some reports I've read, they can
last
even 200-300mS, which is a lot for a 20V-rated component to handle.
So the input to the PSU (I've used the national simple switcher also,
and it looks good) is good to protect (I've used a "trans-zorb").

It also seems to be good to design the PSU so, that it will work from around
7-8V,
since the voltage can drop momentary there on cold cranking!


  -KWi-
  kwi at mamma.icl.fi