Plot I-V Curve
==============
Here we plot voltage across an element against the current flowing though it. The current is calculated from the voltage across a series resistance. The graph of resstors is a straiight line, but not for non-linear elemets like the diodes. 

**Objective**

Plot the I-V curve of several circuit elements.

**Procedure**

.. image:: schematics/res-compare.svg
	   :width: 300px

- Connect the resistors as shown in the figure.
- R2 is used for measuring current, generally 1000 Ohms
- Current through the circuits is Voltage at A1 / R2
- PV1 is varied is steps. Voltage across R1 with current is plotted

.. image:: pics/plot-iv-screen.png
	   :width: 500px
