Current measuring

Thread Starter

ifithegr8

Joined Feb 5, 2010
7
I want to measure current ranging from0 - 1 A max i was planing to Try two things 1.make reference of ADC0831 to 1 V and use 1 ohm resistor connected serially to load and measure voltage along it.
2.Try Digitlizing current flow schematic in datasheet of ADC0831.

what should i do

using 89c51 and adc0831
 

t06afre

Joined May 11, 2009
5,934
Post you schematics young man
1 A max i was planing to Try two things 1.make reference of ADC0831 to 1 V and use 1 ohm resistor connected serially to load and measure voltage along it.
This was not a bad base idea. Why did iy work?
 

Thread Starter

ifithegr8

Joined Feb 5, 2010
7
i think this should work see if i have 1 ohm resistor used.and i should measure voltage across it for current

1.Make VREF = 1 V
that will give me 1/256 = 3.9mv resloution i think not bad
2.In code make equation to convert adc val to voltage as follow

current = adc_rec_val/256 *Vref;

am i write?
 

atferrari

Joined Jan 6, 2004
3,774
Take a look at Phidget1118 current sensor.
Hear of them but did not suspect their price! Not for an occasional use, really.

The use of a resistor seems appealing.

There are cheaper ICs (Maxim or Burr Brown?)

The OP did not say what is the voltage wrt ground at the point where he wants to measure current. A point of concern...

There are lot of circuits with inexpensive opamps that could fit.
 
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