Unit 3.4 Negative Resistance

# Unit 3.4 Negative Resistance - Using a Current Source… f...

This preview shows pages 1–2. Sign up to view the full content.

1 Unit 3: Other Circuit Analysis Techniques Unit 3.4 - Negative Resistance Consider the circuit below… 10V 1 10 Ω 50 Ω 10 Ω + V 1 - f No independent sources f To find Thévenin Equivalent, you must apply an independent source to the output terminals Add a test source--1A -20 = 1 20V - = 1 V = I V = R -20V = V , 6 V = ) 50 + 10 10 ( V = V 0 = 1 - 60 V + 10 ) 10V - (V test test test th test test test 1 test 1 test Solving 10V 1 10 Ω 50 Ω 10 Ω + V 1 - Itest=1A + Vtest - Solve for Vtest: The Thévenin Equivalent Circuit 10V 1 10 Ω 50 Ω 10 Ω + V 1 - Rth = -20 Ω How Can this Be? f Can only have negative resistance with dependent sources f The negative resistance describes the terminal behavior of the original circuit f When an independent source is attached to the terminals, the original dependent source supplies power 10 V source applied I = 10/(-20) = -.5A Power absorbed by 10V source= 5W Rth = -20 Ω 10V I= -.5A

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Using a Current Source… f If we apply an independent current source, the original dependent source supplies power to it as well… V = 2(-20) = -40V Power supplied to independent source = 80W Rth = -20 Ω 2A + V = -40V-2 An Op-Amp Circuit Realization 1k Ω 9k Ω 50 Ω 10 Ω +-10 Ω 10V 1 10 Ω 50 Ω 10 Ω + V 1-The original circuit is a model for a circuit using an op-amp in a non-inverting configuration. Summary f A negative Thévenin resistance can be realized using dependent sources f These represent models for actual circuits f A negative Thévenin resistance means the dependent sources in the original circuit supply power to any independent sources connected to its terminals...
View Full Document

## This note was uploaded on 08/27/2009 for the course EE 16200 taught by Professor Williamneal during the Fall '08 term at University of Texas.

### Page1 / 2

Unit 3.4 Negative Resistance - Using a Current Source… f...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online