1. RLC Circuits

2. An AC circuit is made up with components. Power source Resistors Capacitor Inductors Kirchhoff’s laws apply just like DC. Special case for phase Ohm for AC R C L

3. A series RLC circuit can be made from each component. One loop Same current everywhere Reactances are used for the capacitors and inductors. The combination of resistances and reactances in a circuit is called impedance. Series RLC i R L v C

4. Phase shifts are present in AC circuits. +90° for inductors -90° for capacitors These can be treated as if on the y-axis. 2 D vector Phasor diagram Vector Map VL=IXL VR=IR VC=IXC

5. Vector Sum • The current is the same in the loop. • Phasor diagram for impedance • A vector sum gives the total impedance. XL XL XC Z R R XC

6. The total impedance is the magnitude of Z. The phase between the current and voltage is the angle f between Z and the x-axis. Vector Sum XL XC Z f R

7. Phase Changes • The phase shift is different in each component.

8. Power loss in an AC circuit depends on the instantaneous voltage and current. Applies to impedance The cosine of the phase angle is the power factor. Power Factor P 0 t next