4.3 - Electricity - Electrical Circuits Flashcards
What is Kirchhoff’s second law
In a closed loop in a circuit, the sum of potential differences is qual to the sum of the electromotive force.
(this is conservation of energy)
In a series circuit how do you find the total resistance of a circuit containing resistors in series
Rtotal = R1 + R2 + R3 + …
In a parallel circuit how do you find the total resistance
1/Rtotal = 1/R1 + 1/R2 + 1/R3 + …
Does adding resistors in a parallel circuit reduce the total resistance
Yes, the total resistance drops the more paths there are for the current to take
How is an ammeter connected
In series
How is a voltmeter connected
In parallel
How to find the total voltage in a parallel circuit
Vtotal = V1 = V2 = V3
How to find the total voltage in a series circuit
Vtotal = V1 + V2 + V3 + …
How does current act in a series circuit
It is constant through all of the components and is the same
How does current act in a parallel circuit
Each branch has a different current.
As the voltage across each branch is the same the different resistances mean they have different currents
What is the total emf equation fit here is more than one cell in series (positive to positive)
ϵtotal = ϵ1 + ϵ2
What is the total emf equation fit here is more than one cell in series (negative to negative)
ϵtotal = ϵ1 - ϵ2
They would cancel each other out
What is internal resistance
It is the resistance within a power source due to the materials of the component
What are lost volts
They are the difference between the voltage supplied by the source and the amount available to the circuit
Equation for emf and both internal and load resistance
ϵ = I (R+r)
emf = current (Load resistance x internal resistance)
