Thread: 3 bux
View Single Post
  #6   Report Post  
Posted to alt.binaries.schematics.electronic
Jasen Betts[_2_] Jasen Betts[_2_] is offline
external usenet poster
 
Posts: 331
Default 3 bux

On 2015-10-10, ehsjr wrote:
On 10/9/2015 5:38 AM, Jasen Betts wrote:
On 2015-10-09, Robert Baer wrote:
Jasen Betts wrote:
Impossible for power out to be greater than power in.


I said it's a good deal if you don't look too closely.


Possibly it's measuring average current and voltage, and not RMS.
Or it mught just be reading innacurately. It was like $7 and
change for the pair.


Or the in and out labels are in the wrong places and you have
an 87% efficient boost DC-DC converter. :-)

For what they are, it's really not too bad. 4 meters - $1.50 per
meter - with maybe +/- 3.3% error each. At that low cost, they
undoubtedly were not "factory calibrated". So if you wanted to take
the time and effort, you might be able to spin a pot and file
(or add solder to) a shunt to get better accuracy. But really,
these meters should be used just to give one a rough idea of
voltage & current.


I'll swap them on monday and see if the error moves, and also do
some comparisons against some slightly more expensive meters.


--
\_(ツ)_