Sinusoids and Phasors Ø Delta-to-wye and wye-to-delta conversions Ø Phase Sifters. Ø AC Bridges. Ø Problem Solutions
Y-Δ and Δ-Y Equivalent Circuits Ø Y-Δ and Δ-Y type equivalent conversions will be most useful when considering Three Phase circuits. Ø Impedances Z 1, Z 2 and Z 3 are Y connected. Ø Impedances Za, Zb and Zc are Δ connected. Ø Y and Δ forms can be eqivalently converted from one form to the other. Ø Y-Δ and Δ-Y conversions are valid for impedances as well as resistive circuits.
Y-Δ and Δ-Y Equivalent Circuits Ø Y-Δ and Δ-Y type equivalent conversions will be useful when considering Three Phase circuits in Chapter 12.
Balanced Y-Δ and Δ-Y Equivalent Circuits Ø A delta (Δ) or Y (wye) circuit is balanced if it has equal impedances in all three branches. Ø Y-Δ and Δ-Y conversions is very simple for balanced circuits.
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
P. P. 9. 12 Continued
Phase Shifters (Leading Output) Ø Phase shifting is employed to correct undesirable phase shift of the AC voltage. Leading Output Leads the input
Phase Shifters (Lagging Output) Ø Phase shifting is employed to correct undesirable phase shift of the AC voltage. Lagging Output Lags the input
P. P. 9. 13 Design an RC circuit that provide 90° lagging phase shift. Find the output voltage if 10 Volt is applied.
AC Bridges Ø 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
AC Bridges Ø 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.
Chapter 9, Problem 41.
Chapter 9, Problem 51.
Ch 9, Prob 55. Find Z in the network given that
Chapter 9, Problem 77 a) Calculate the phase shift at 2 Mhz. b) Calculate the frequency at which phase shift is 45 degree.
Chapter 9, Problem 77 a) Calculate the phase shift at 2 Mhz. b) Calculate the frequency at which phase shift is 45 degree.