In a circuit containing dependent sources, maximum power transfer occurs when the load resistance equals what?

In a circuit containing dependent sources, maximum power transfer occurs when the load resistance equals what?

• A. The Thevenin resistance seen by the load with dependent sources active
• B. The Thevenin resistance ignoring dependent sources
• C. Infinity
• D. Zero

Answer: (A)

Maximum power transfer occurs when the load resistance equals the Thevenin resistance “seen” by the load. In circuits with dependent sources, you must include those sources when determining what the load actually sees. That means turning off independent sources but leaving the dependent sources active, and often using a test source to measure the resulting voltage and current to find the Thevenin resistance. With this Thevenin resistance properly found, the load should be adjusted to match it. If you ignore the dependent sources, you’ll get an incorrect Thevenin resistance, and the condition R_L = R_th won’t guarantee maximum power.

Maximum power transfer occurs when the load resistance equals the Thevenin resistance “seen” by the load. In circuits with dependent sources, you must include those sources when determining what the load actually sees. That means turning off independent sources but leaving the dependent sources active, and often using a test source to measure the resulting voltage and current to find the Thevenin resistance.

With this Thevenin resistance properly found, the load should be adjusted to match it. If you ignore the dependent sources, you’ll get an incorrect Thevenin resistance, and the condition R_L = R_th won’t guarantee maximum power.