This document contains instructions for block diagram reduction. It provides 5 rules for reducing block diagrams: 1) blocks in series combine by multiplication, 2) blocks in parallel combine by addition, 3) a feedback loop divides the forward path, 4) blocks still in series after previous steps combine by multiplication, and 5) a remaining feedback loop contributes an additional term of 1 in the denominator. An example problem demonstrates applying these rules to determine the transfer function of a block diagram.

1. Prof. Mrs. S.S. Gondkar Department
of Electrical Engineering.
1
Sanjivani College of Engineering, Kopargaon
Department of Electrical Engineering
(An Autonomous Institute)
Affiliated to Savitribai Phule Pune University
Accredited ‘A’ Grade by NAAC
_________________________________________________________________
Numerical on Block Diagram Reduction.

2. G1
G3
G2
G4
H1
H2
Example1:Determine the TF
+ +
+
+
+
-

3. G1
G3
G2
G4
H1
H2
+ +
+
+
+
-
Rule 1: blocks in series
G1 G4 G1G4

4. G3
G2
H1
H2
+ +
+
+
+
-
Rule 2: Blocks in Parallel
G1G4
G2
G3
G2+G3

5. G2+G3
H1
H2
+ +
+
+
-
Rule 3: Feedback loop
G1G4
G1G4
H1
+

6. G2+G3
H2
+
+
-
Rule 4: Blocks in series
+
G2+G3

7. H2
+
-
Rule 5 Feedback loop
+

8. 1+

9. G(S)=

10. Prof. Mrs. S.S. Gondkar Department of
Electrical Engineering.
10
Thank You!