Amplifier Output Resistance Calculator

Understanding Amplifier Output Resistance

The output resistance ($R_{out}$) of an electronic amplifier is a fundamental parameter that determines how well the system can drive various loads without experiencing significant voltage drops. In an ideal voltage amplifier, the output resistance is zero, meaning the output voltage remains completely constant regardless of the attached load impedance. However, real-world amplifiers possess internal Thévenin resistance caused by active components like transistors, operational amplifiers, and biasing networks.

Formula Used

Depending on the measurement method selected, different mathematical formulations are applied:

• Load Voltage Method: $$R_{out} = R_L \times \frac{V_{NL} - V_{FL}}{V_{FL}}$$
• Open/Short Circuit Method: $$R_{out} = \frac{V_{OC}}{I_{SC}}$$
• Gain Drop Method: $$R_{out} = R_L \times \frac{A_{v(oc)} - A_{v(fl)}}{A_{v(fl)}}$$

How to Use This Calculator

To compute the output resistance efficiently, choose your preferred measurement approach from the first layout column. Input your specific laboratory or simulation values into the corresponding data fields within the second column. Finally, click the calculation trigger button to review the computed output resistance results displayed securely above the operational parameters panel.

Frequently Asked Questions (FAQs)