1. Chapter 9 Sinusoids and Phasors
5/27/2018
Chapter 9 Sinusoids and Phasors
Delta-to-wye and wye-to-delta conversions
Phase Sifters.
AC Bridges.
Problem Solutions
Huseyin Bilgekul Eeng224 Circuit Theory II Department of Electrical and Electronic Engineering Eastern Mediterranean University

2. Y-Δ and Δ-Y Equivalent Circuits
Y-Δ and Δ-Y type equivalent conversions will be most useful when considering Three Phase circuits.
Impedances Z1, Z2 and Z3 are are Y connected.
Impedances Za, Zb and Zc are Δ connected.
Y and Δ forms can be eqivalently converted from one form to the other.
Y-Δ and Δ-Y conversions are valid for impedances as well as resistive circuits.

3. Y-Δ and Δ-Y Equivalent Circuits
Y-Δ and Δ-Y type equivalent conversions will be useful when considering Three Phase circuits in Chapter 12.

4. Balanced Y-Δ and Δ-Y Equivalent Circuits
A delta (Δ) or Y (wye) circuit is balanced if it has equal impedances in all three branches.
Y-Δ and Δ-Y conversions is very simple for balanced circuits.

5. Find I in the circuit given?
Converting Δ Connection to Y form, we obtain
Converting to Y form, we can simplify the circuit by combining the parallel and series elements Z

6. P.P.9.12 Continued

7. Phase Shifters (Leading Output)
Phase shifting is employed to correct undesirable phase shift of the AC voltage.
Leading Output.
Output Leads the input

8. Phase Shifters (Lagging Output)
Phase shifting is employed to correct undesirable phase shift of the AC voltage.
Lagging Output.
Output Lags the input

9. P. P. 9. 13 Design an RC circuit that provide 90° lagging phase shift
P.P.9.13 Design an RC circuit that provide 90° lagging phase shift. Find the output voltage if 10 Volt is applied.

11. A general AC bridge circuit
AC Bridges
The AC bridge is Balanced when no current flows through the meter. AC bridges are used in measuring inductance and capacitance values.
A general AC bridge circuit

12. AC Bridges
Unknown capacitance and inductances Cx and Lx are measured in terms of the known standard values Cs and Ls
AC Bridge for measuring L
AC Bridge for measuring C.

14. Chapter 9, Problem 41.

15. Chapter 9, Problem 51.

16. Ch 9, Prob 55. Find Z in the network given that

17. Chapter 9, Problem 77 a) Calculate the phase shift at 2 Mhz.
b) Calculate the frequency at which phase shift is 45 degree.

18. Chapter 9, Problem 77 a) Calculate the phase shift at 2 Mhz.
b) Calculate the frequency at which phase shift is 45 degree.