![Page 1: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/1.jpg)
Aim: How can we explain parallel circuits?
Do Now:
A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance?
RT = R1 + R2 + R3
RT = 20 Ω + 40 Ω + 60 Ω
RT = 120 Ω
RT in series is always larger than the largest resistor!
![Page 2: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/2.jpg)
Parallel Circuits
•A circuit with 2 or more current loops
![Page 3: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/3.jpg)
Draw 2 resistors and a battery in a parallel circuit
![Page 4: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/4.jpg)
Or…
![Page 5: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/5.jpg)
Or…
![Page 6: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/6.jpg)
Light Bulb Demo
If one goes out, the others remain lit
![Page 7: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/7.jpg)
In a parallel circuit…
• Voltage is constant
• Total current is the sum of the currents through each resistor
![Page 8: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/8.jpg)
And resistance…
Straw Demo
RT in parallel is always smaller than the smallest resistor!
![Page 9: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/9.jpg)
R1 = 10Ω, R2 = 20Ω, R3 = 30Ω, in parallel with a VT = 100V
• Draw this circuit
• Calculate the current though each resistor
R1 = 10Ω R2 = 20Ω R3 = 30Ω
VT = 100V
![Page 10: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/10.jpg)
V I R
1 100V 10 A 10Ω
2 100V 5 A 20Ω
3 100V 3.3 A 30Ω
T 100V 18.3 A 5.5 Ω
![Page 11: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/11.jpg)
Draw a parallel circuit with a battery, 3 resistors, an ammeter reading the current through R1 and an ammeter reading the current through R3. R1 = 2Ω, R2 = 4Ω, R3 = 8Ω, and the ammeter for R3 reads 2.5 A.
R1 = 2ΩR2 = 4Ω
R3 = 8Ω
I3 = 2.5A
![Page 12: Aim: How can we explain parallel circuits? Do Now: A series circuit has 3 resistors, 20 Ω, 40 Ω, and 60 Ω. What is the total resistance? R T = R 1 + R](https://reader035.vdocuments.site/reader035/viewer/2022062421/56649e375503460f94b27b15/html5/thumbnails/12.jpg)
V I R
1 20V 10 A 2Ω
2 20V 5 A 4Ω
3 20V 2.5 A 8Ω
T 20V 17.5 A 1.1 Ω