# HELP!!!...plotting graph of components V and A

#### raza88sab

Joined Oct 19, 2007
1  hiya i need help with this homwork i carried out the experiment in lesson and i took down the readings V and A using the multimeter, what ever the teacher wrote i have written below if anyone would help me thanks in advance.............here goes. (i have attacted the file which has the readings i recorded while carrying out the experiment.

plot the graph of Current (y-axis) against Voltage (x-axis) on a sheet of linear graph paper. From this graph the resistance can be found by drawing a line of best fit and then measuring the gradient and inverting
it. (N.B. The actual gradient of the graph di/dv is called the conductance. The SI unit is the Siemen or S for short.) Once you have calculated a value, measure the value of the resistor using the multimeter and compare it with

Question 1: How does the calculated value of the resistor obtained from the gradient of the graph compare to the measured value of the resistor?
(DMM i think is the Digital multimeter i used and all the readings are attacted)

Value from graph:
Value from DMM:

Question 2: What could be the cause of any variation in the values?

Question 3: What was the maximum power dissipated by the resistor during your tests?

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#### beenthere

Joined Apr 20, 2004
15,819
Are you familiar with Ohm's Law, and how it might apply to your project? Do you know how to calculate power?

#### JoeJester

Joined Apr 26, 2005
4,259
DMM is the Digital Multi Meter as you suspect.

How did you wire the components you've listed? Attach the schematic if you can.

Somehow I doubt you applied 30 amperes into any circuit as a student.

#### JoeJester

Joined Apr 26, 2005
4,259
Now that you provided the diagram, I suspect you were to test each component individually incrementing the power source from 0 to 30 ... or 0 to negative 30, while measuring the current through and voltage across the component.

It's easier if you draw the circuits individually ... so you calculate what it is, and then what you measure.

#### JoeJester

Joined Apr 26, 2005
4,259
I'm curious why you chose those incremental values. Furthermore, in lieu of sending me messages, post your replies in the forum.

It would be far easier if you choose a linear incremental value.