{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

6 DC Circuit III

# 6 DC Circuit III - ELEC101 DCcircuits66 2010/11Spring...

This preview shows pages 1–6. Sign up to view the full content.

ELEC 101 DC circuits 66 2010/11 Spring Equivalence Two resistive one-port networks are equivalent if they have the same current- voltage (I-V) curve across the two terminals for ALL loads (or sources). V1 Network A load R I1 V2 Network B load R I2 Hence a complex network (Network A) can be replaced by a simple equivalent (Network B) and network analysis can be simplified. If I1 = I2 and V1 = V2 for ALL load R , then network A and network B are equivalent . ( A B ) Example NO. I1 I2 and V1 V2 for other R. For example, when R = 6 , I1 = 0.5A, V1 = 3V ; I2 = 2/3A, V2 = 4V Is network A equivalent to network B ?? 2 6 8V R = 2 4V R = 2 I1 = 1A I2 = 1A V1 = 2V V2 =2V network A network B Example

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

View Full Document
ELEC 101 DC circuits 67 2010/11 Spring Network A equivalent to network B ? ( YES. For ALL R , I1 = I2, V1= V2 ) network A network B 2 4V 4 8V 4 R R I2 V2 V1 I1 Example network A network B 2 4V 4 8V 4 R R I2 V2 V1 I1 When R = 0 (short) A V I V V 2 2 4 1 0 1 A V I V V 2 4 8 2 0 2 network A network B 2 4V 4 8V 4 R R I2 V2 V1 I1 When R =  (open) V V A I 4 1 0 1 2 0 8 2 4 4 8 I A V V V   a b I1 I2 V1 For example, when R = 2 , I1 = 1A, V1 = 2V ; I2 = ?, not easy to calculate.
ELEC 101 DC circuits 68 2010/11 Spring For network A The I1-V1 curve for all R is the line joining R = 0 and R = . The curve is a straight line as the I-V curve for a resistive circuit is linear. For network B c d Hence I1-V1 curve = I2-V2 curve. Hence network A and network B are equivalent . e Similarly the I2-V2 curve is a straight line. I2 V2 2A 4V R = 0 R = 0 I1 V1 2A 4V R = 0 R = 0 In general, such a straight line is called the load line of the circuit

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

View Full Document
ELEC 101 DC circuits 69 2010/11 Spring Load line A load line is a straight line in a current voltage plot Useful for analyzing nonlinear circuit elements and loads Also useful for power analysis Assume the load to be 0 and ohms (short circuit and open circuit situations) Kirchhoff’s voltage law : Complex circuit with power supply Load R V o I V V IR V o I V Close circuit current = V o /R Open circuit voltage = V o Load line
ELEC 101 DC circuits 70 2010/11 Spring 7 Example 7 18V V 1 I 1 Show that network A and network B are equivalent. 36V 3 6A 4 R I 2 V 2 1. when R = 0 (short) , 1 1 0 18 18 7 7 V V V I A 2 2 2 2 0 36 3 (6 ) 4 18 18 7 7 V V V A I I V I A   2. when R =  (open) , 1 1 0 18 I A V V 3. I 1 -V 1 curve = I 2 -V 2 curve Network A Network B Hence network A and network B are equivalent . R 18V 36V 3 6A 4 V 18 3 A 6 V 36 V source A 6 across voltage V A 0 I 2 2 2 3k 1k 12V O I 6k 3k 3V 2k Find I O .

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.

{[ snackBarMessage ]}

### Page1 / 27

6 DC Circuit III - ELEC101 DCcircuits66 2010/11Spring...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online