Mechanical/Electric Scales Query

Kaiju · 12 Jul 2007 at 22:01

I've now weighed myself on four mechanical scales and three electric scales and I weigh one amount on the mechanical scales and another amount on the electric scales.

My question is does anyone know why the amounts are different?

Millwall.FC · 12 Jul 2007 at 22:07

calibration is out on one of them. get a third opinion

Kaiju · 12 Jul 2007 at 22:09

So weird that all four mechanical scales say the same weight and the three digital scales say the same other weight. All four mechanical scales must be calibrated wrong.

Downsy · 12 Jul 2007 at 22:11

Mainly because they aren't calibrated correctly, there is a lot which can be wrong with them (depending on the price).

Both types work using a spring element and either use the deflection to move a needle or measure the extension of the spring using a strain gauge (measures the change in resistance as the grid on the gauge extends). As I doubt most mass produced scales are correctly calibrated then it's very difficult to get a true reading, even the same scales will measure differently dependent on the temperature, surface it is sitting etc.

Millwall.FC · 12 Jul 2007 at 22:12

my bad i read your first post wrong i thought you said 2 scales :S

very strange add em all up and go for the average,

SiriusB · 12 Jul 2007 at 22:22

Mechanical scales are analogue and can give you pretty much any value on the scale.

Electric scales are digital and as such has discrete values. If you weight comes in between two values it will round up or down to the nearest value. The better the scales the more discreet values it will have and the more accurate it will be.

How different is the readings from the two scales? If it's a very small amount, don't worry. If it is large - buy better scales

Kaiju · 12 Jul 2007 at 22:41

Clever me, just used two 5kg dumbells to check both my scales and the digital scales are always accurate while the mechanical ones are only accurate if positioned a certain way.

The mechanical scales are between 0.5-1.5kg out dependant on where the weights are placed. I'll have to let my doctor know, as his mechanical scales are not fully accurate.