Resistance Meter

Chipper

Is there anyway you could make the stamp read a resistance value with an ADC, i have it reading voltage already any ideas. I tried V=IR but i dont know how to solve for the current. I was guessing i could use the ADC to measure voltage drop and use that but im lost.......any help would be appriciated·· Thankyou [noparse]:D[/noparse]

Mike Green

There are many ways you could do this. For example, you could put a fixed, known resistance in series with the unknown resistance and measure the voltage drop across this. If you have a fixed known voltage supply (like +5V), you can determine the unknown resistance. The voltage drop across the known resistance gives you the current through it (I = E / R). The same current is flowing through the unknown resistance and the voltage across the unknown resistance is known (5 - E). You can compute the unknown resistance ((5 - E) / (E / R)).