epicours/Electronic/Lecture 1.md

<img src="https://i.imgur.com/ZPadVTR.jpg" /img>

E : the voltage corresponding to Ua - Ub = Uab V = Ub - Uc The current correponding to the flow of electrical electrons from A to C in A

Dipoles : component between two points of the diagram Ohm's law: V=R \times{I}

<img src="https://i.imgur.com/a9skJL3.png" /i>

Association of resistors

resistors in serie

R_{1} and R_{4} get the same flow (current). Replace R1 and R4 by R_{s} = R_{1}+R_{4}

Resistors in parallel

R_{2} and R_{3} see the same voltage: U_{2} = U_{c}-U{b}, U_{3} = U_{d}-U{b} and U_{d} = U_{c} R_{2} and R_{3} are replaced by R_{P} : R_{P}=\frac{R_{3}\times{R_{2}}}{{R_{3}+R_{2}}}

Definitions

• A branch is a link between 2 points in the diagram
• A node is a point in the diagram linked to at lease 3 branches
• A loop is a draw from a point in the diagram to itself.

⚠️ In a loop we don't use the same path twice or more

Exemple:

flowchart LR
	C --> D --> B --> C

flowchart LR
	A --> C --> B --> A

Different laws

Kirchhoff's laws

• The addition of voltages in a loop = 0 exemple : V_{AC} + V_{CB} + V_{BA} = 0
• The algebraic sum of currents into a node = 0 Exemple : \text{Node(C)} = I - I_{2} - I_{3} = 0

Kirchhoff's laws & Ohm's law

We can't calculate I, I_{2} and I_{3}