100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
EBN111 summary 1st year Mechanical Engineering $5.91   Add to cart

Class notes

EBN111 summary 1st year Mechanical Engineering

 94 views  2 purchases
  • Course
  • Institution
  • Book

This document contains all the equations needed for EBN111. It also contains explanations on all theorems in the chapters from 1-6 and 9-10 in the book.

Preview 2 out of 9  pages

  • July 7, 2021
  • 9
  • 2021/2022
  • Class notes
  • Dr derik le roux, dr xianming ye, dr suzanne smith
  • All classes
avatar-seller
EBN 111
𝑞 𝑣
Current: 𝑖 = or 𝑖=
𝑡 𝑅
𝑤 If current enters through
Voltage: 𝑉 = or 𝑉 = 𝑖𝑅
𝑞 -ve then p=-vi
𝑤 𝑣2
Power: 𝑝 = or 𝑝 = 𝑣𝑖 or 𝑝 = 𝑖2𝑅 or 𝑝=
𝑡 𝑅
𝑡
Charge: 𝑄 ≜ ∫𝑡 𝑖 𝑑𝑡
0

𝑡 𝑡
Energy: 𝑤 = ∫𝑡 𝑝 𝑑𝑡 = ∫𝑡 𝑣𝑖 𝑑𝑡
0 0

𝑣𝑖
Cost: 𝑐𝑜𝑠𝑡 = × (𝑡𝑖𝑚𝑒 𝑖𝑛 ℎ𝑟𝑠) × 𝑐𝑜𝑠𝑡 𝑖𝑛 𝑟𝑎𝑛𝑑𝑠 𝑝𝑒𝑟 ℎ𝑟
1000
ℓ 𝑣
Resistance: 𝑅 = 𝜌 or 𝑅=
𝐴 𝑖
1 𝑖
Conductance: 𝐺 = or 𝐺=
𝑅 𝑣

Nodes, Branches and Loops: 𝑏 = 𝑙 + 𝑛 − 1
KCL: 𝑐𝑢𝑟𝑟𝑒𝑛𝑡𝑠 𝑖𝑛 = 𝑐𝑢𝑟𝑟𝑒𝑛𝑡𝑠 𝑜𝑢𝑡
KVL: 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 𝑑𝑟𝑜𝑝𝑠 = 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 𝑟𝑖𝑠𝑒𝑠
Resistors in series: 𝑅𝑒𝑞 = 𝑅1 + 𝑅2 + ⋯ + 𝑅𝑁
𝑅1 𝑅2
𝑣1 = 𝑣 𝑣2 = 𝑣
𝑅1 +𝑅2 𝑅1 +𝑅2
𝑅1 𝑅2
Resistors in parallel: 𝑅𝑒𝑞 = only for 2 resistors in //
𝑅1 +𝑅2
1 1 1 1
= + + ⋯+
𝑅𝑒𝑞 𝑅1 𝑅2 𝑅𝑁

𝑅2 𝑖 𝑅1 𝑖
𝑖1 = 𝑖2 =
𝑅1 +𝑅2 𝑅1 +𝑅2
𝑅𝑏 𝑅𝑐 𝑅𝑎 𝑅𝑐 𝑅𝑎 𝑅𝑏
Delta to Wye: 𝑅1 = 𝑅2 = 𝑅3 =
𝑅𝑎 +𝑅𝑏 +𝑅𝑐 𝑅𝑎 +𝑅𝑏 +𝑅𝑐 𝑅𝑎 +𝑅𝑏 +𝑅𝑐
𝑅1 𝑅2 +𝑅2 𝑅3 +𝑅3 𝑅1 𝑅1 𝑅2 +𝑅2 𝑅3 +𝑅3 𝑅1
Wye to Delta: 𝑅𝑎 = 𝑅𝑏 =
𝑅1 𝑅2
𝑅1 𝑅2 +𝑅2 𝑅3 +𝑅3 𝑅1
𝑅𝑐 =
𝑅3

, Nodal Analysis: Use KCL to find voltage of nodes.
Steps:
1. Select a node as a reference node.
2. Assign voltages 𝑣1, 𝑣2 , … 𝑖1 𝑣1 𝑖2
3. Point currents going out of the nodes.
4. Current sources flowing toward the node will be 𝑖3
negative in the equation and current sources flowing
away from the node are positive.
5. If there is a voltage source in between the reference and a node then
the nodes voltage is equivalent to the source.
𝑣
6. Create an equation at each node using ohms law by saying 𝑖 = , 𝑣 =
𝑅
𝑛𝑜𝑑𝑒 𝑦𝑜𝑢 𝑎𝑟𝑒 𝑎𝑡 − 𝑡ℎ𝑒 𝑛𝑜𝑑𝑒 𝑦𝑜𝑢 𝑎𝑟𝑒 𝑔𝑜𝑖𝑛𝑔 𝑡𝑜
7. If there is a supernode where a voltage source is in between two nodes
then switch off the source and use KCL.
8. Use simultaneous equations to solve for node voltages.
Mesh Analysis: Use KVL to find currents in loops.
1. Current always flows in the clockwise direction inside the loop.
2. If a current source flows in the opposite direction
to 𝑖1 then it is negative and vise versa. The current
source is the current in the loop. 𝑖1
3. When resistors are inbetween two loops then in the
equation you will say
𝑅(𝑙𝑜𝑜𝑝 𝐼 ′ 𝑚 𝑖𝑛 − 𝑡ℎ𝑒 𝑜𝑡ℎ𝑒𝑟 𝑙𝑜𝑜𝑝 = 𝑅(𝑖1 − 𝑖2 )
4. When writing the equations use the formula 𝑣 = 𝑖𝑅
5. If there is a supermesh where there is a current source being shared
between two meshes then you switch off the current source and assume
meshes 1 and 2 is one single mesh(BUT still use the different mesh
currents).
6. Create a simultaneous and solve.

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller aidendt. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $5.91. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

73314 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
$5.91  2x  sold
  • (0)
  Add to cart