# I Combined circuits

1. Mar 3, 2016

### Steelers72

I am doing a lab experiment with regard to combined circuits, and I wanted to check my data to see if I made an error in my experiment.

Theoretically speaking, in a combined circuit, should Itotal (total current) be equivalent to the Imeasured value?

I calculated my Itotal to be .0292A since the Vbatteries/Rtotal = 2.492V/84.23ohm

However, my Imeasured was 0.3253A +/- 0.0001A

To get the equivalent Resistance I had to break the circuit into series (Rtotal= R1+R2...) and parallel (1/Rtotal= 1/R1+1/R2) components.

I am confused what the "take home point" or rule for combination circuits should be, since my Itotal and Imeasured are so far off.

Thanks for any help

2. Mar 3, 2016

### Simon Bridge

By "combined circuits" do you mean like this:
http://www.physicsclassroom.com/class/circuits/Lesson-4/Combination-Circuits

I don't know what you mean by "total current".
The measured current should be whatever you measured.
You will presumably compare it to some theoretical value ... which should be calculated as the current passing through the part of the circuit diagram corresponding to the position of the ammeter in the actual circuit.

Double check you maths - make sure you calculated the current for where the ammeter is.
If your math result is outside 2sd from the measurement, then you say that the measurement does not support the theory used.
It may be that the physical circuit does not match the diagram, or that you made a mistake in the maths.
Did you check your calculation for the equivalent resistance by measuring it with an ohmmeter?