1. Fall 2001ENGR-201 Maximum Power Transfer 1 Maximum Power Transfer If a load resistor R L is connected to a linear circuit, what value of R L results in maximum power being delivered to the load? Read: pages 131- 133Problems: 4FE-2 Linear Circuit A B RLRL To answer the question, replace the linear circuit by the Thevenin equivalent.

2. Fall 2001ENGR-201 Maximum Power Transfer 2 Determining R L

3. Fall 2001ENGR-201 Maximum Power Transfer 3 P L is a Function of R L The power is a function of R L. The values of V TH and R TH are constant (not affected by changes in R L ). Therefore, we need to determine the value of R L that maximizes the value of P L. P max R max How do we find R max ? Short Circuit (R L =0  ) Open Circuit (R L =  )

4. Fall 2001ENGR-201 Maximum Power Transfer 4 P max R max Determining the Value of R max We find the point of inflection (point where slope of function = 0). Maximum power transfer occurs when the load is equal to the value of the Thevenin equivalent resistance.

5. Fall 2001ENGR-201 Maximum Power Transfer 5 Determining P max For Maximum power Transfer: