JIMMIE wrote:
On Dec 19, 10:07 am, wrote:
On Dec 19, 2:25 am, mm wrote:

On Thu, 18 Dec 2008 18:04:36 -0700, Tony Hwang
wrote:
mm wrote:
How many things do you know of where a voltmeter shows no voltage, but
the device works fine?
I bought an auto/air laptop power supply for a friend of mine, and it
was a good brand (Targus) and it's hard to imagine too high a voltage
coming from a car, but since it wasn't my computer, I thought I should
check the voltage before plugging it into his new laptop.
So, out in the car, I measured the voltage and got zero. Even though
the light was on on the brick.
does the device have a multi-pin connector i.e. more than 2 pins?

I think that device needs to see a programming resistor to tell it
what voltage to output..

No resistor, no output.

It has nothing to do with series vs parallel regulators.

Mark

I doubt if its a series regulator or a parallel regulator. I would
have to be a switching regulator and these just shut down under no
load conditions. This is to protect the internal circuitry of the
regulator which would soon let all the smoke out if operated without a
load.


Jimmie
Hi,
There is no switching regulator. Switching power supply is follwed by a
regulator circuit. Crow bar circuit is for protection.