Source and Load Matching: DC perspective

Have you ever wonder why people talk about source and load matching? I did, and one thing that I asked my self is whether I have something in DC domain that can help me to visualized it. Well see below for my way of understanding source and load matching.

Supposed that we have a circuit as shown below:

From there we can create a table of maximum possible power that Rl can pull out of the source Vs:

Vs	Rs	Rl	Vo = VS * (Rl/(Rs+Rl))	Pout = (Vo^2)/Rl
1	1	0	0.00	-
1	1	0.2	0.17	0.14
1	1	0.4	0.29	0.20
1	1	0.6	0.38	0.23
1	1	0.8	0.44	0.25
1	1	1	0.50	0.25
1	1	1.2	0.55	0.25
1	1	1.4	0.58	0.24
1	1	1.6	0.62	0.24
1	1	1.8	0.64	0.23
1	1	2	0.67	0.22

From the table we can plot out the load power as Rl changes – as you can see, max Pout occurs when Rl “match” Rs, which is 1 Ohm in this example