Dual slope integration help

Thread Starter


Joined Aug 9, 2012
I'm trying to design a Dual slope integrator for a digital power meter,the problem i'm facing is that i dont quite understand how the dual slope integrator works.

I know that it uses a fixed period of time to charge a capacitor with an unknown voltage and then uses a negative reference voltage to discharge it whilst tiiming the run down.
  1. What i don't get is whether the fixed period of charging is determined by the RC network or by the controller?
  2. I know once the run down phase begins,the controller counts the number clock pulses coming in,and then obtains the run down period from that,Its the whole resolution and sampling rate part i do not understand.
  3. How do you change the whole thing so that you'll measure current?Do you do it in the microcontroller or
Please help


Joined Mar 14, 2008
To measure current you can measure the voltage across a small shunt resistor in series with the current and calculate the current using Ohm's law.