ECE201 Lect-111 Circuits with Resistor Combinations (2.6, 7.7) Dr. S. M. Goodnick September 19, 2003

ECE201 Lect-112 Solving Circuits with Series and Parallel Combinations The combination of series and parallel impedances can be used to find voltages and currents in circuits. This process can often yield the fastest solutions to networks. This process may not apply to complicated networks.

ECE201 Lect-113 Series and Parallel Impedances Impedances are combined to create a simple circuit (usually one source and one impedance), from which a voltage or current can be found Once the voltage or current is found, KCL and KVL are used to work back through the network to find voltages and currents.

ECE201 Lect-114 1k  2k  1k  2k  1k  +–+– 10V + – V1V1 + – V3V3 + – V2V2 Example: Resistor Ladder Find V 1, V 2, and V 3

ECE201 Lect-115 1k  2k  1k  2k  1k  10V + – V1V1 + – V3V3 + – V2V2 Example: Resistor Ladder Find an equivalent resistance for the network with V 1 across it, then find V 1 using a voltage divider. +–+–

ECE201 Lect-116 1k  10V + – V1V1 Example: Resistor Ladder +–+–

ECE201 Lect-117 1k  2k  1k  2k  1k  10V + – 5V + – V3V3 + – V2V2 Example: Resistor Ladder Find an equivalent resistance for the network with V 2 across it, then find V 2. +–+–

ECE201 Lect-118 Example: Resistor Ladder 1k  2k  1k  10V + – 5V + – V2V2 1k  +–+–

ECE201 Lect-119 1k  2k  1k  2k  1k  10V + – 5V + – V3V3 + – 2.5V Example: Resistor Ladder +–+–

ECE201 Lect-1110 Example: Notch Filter Find V out Use  = k  0.1  100  10V  0  + – V out 70.4mH 100  F +–+–

ECE201 Lect-1111 V out 1k  0.1  100  10V  0  + – j106  –j6.67  Example: Notch Filter Find the equivalent impedance of the resistor, inductor, and capacitor. +–+–

ECE201 Lect-1112 V out 1k  100  10V  0  + – 7.12   –89.99  Example: Notch Filter Combine top resistor and impedance. +–+–

ECE201 Lect-1113 Example: Notch Filter V out 1k  10V  0  + –   –4.07  +–+–

ECE201 Lect-1114 Example #2: Notch Filter Find V out Use  = 377 1k  0.1  100  10V  0  + – V out 70.4mH 100  F +–+–

ECE201 Lect-1115 Example: Notch Filter V out = 1.23V  0.17 

ECE201 Lect-1116 Frequency Response

ECE201 Lect-1117 Class Examples Learning Extension E2.14 Learning Extension E2.15 Learning Extension E7.12