Circuits Flashcards
Conductors allow for
Electron charges to move more freely
What is the function of insulators?
They retard the flow of electricity
How do electrons move in conductors?
They move from low potential to high potential
Electric current is the
Flow of charge
What is the equation of electric current?
I = q / t
In a DC current, the charge flows in
One direction
In an AC current, the charge flows in
Many directions
The direction of current flows
Opposite of electrons, from high to low potential
Voltage is the
Change in current
What is E, or electromotive force?
Voltage across terminals of a cell when there is no current flowing
Electromotive force is basically the potential difference in
Voltage
A cell is discharging when
A cell is supplying current
How is the current when a cell is discharging?
Going from positive to negative
The ∆V equals
V(emf) - IR(cell)
What happens when a cell is being recharged?
Current from another source is sent into the positive terminal
The cell’s internal resistance is able to
Decrease Voltage
What is the equation for Emf?
E = V-IR(int)
What is Ohm’s Law?
V = I • R
Resistance is the
Opposition to flow of current within the conductor
Resistance results in
Energy loss / drop in potential
What is the equation for Resistance of conductor?
R = p (resist) • L / A
How are most conductors at higher temperatures?
They have greater resistance
What is the equation of Power?
P = I • V or V^2 / R or I^2R
Kirchhoff states that at any junction,
∑current (in) - ∑current (out)
What does Kirchhoff think in regards to voltage?
∑Voltage sources = ∑Voltage drops
How does resistance add in a series?
R = R1 + R2 + … + R3
How does resistance add in a parallel?
1 / R = 1 / R1 + 1 / R2 + … + 1 / R3
Dielectrics function to
Disconnect capacitor from the source of charge, decreasing voltage across
What is the function of Capacitors?
They store charge in the circuit based on ∆V between 2 parallel plates
What are Capacitors?
A 2-plate system with a positive plate and a negative plate
Capacitance is measured with the equation
C = Q / V or E • A / d
What is the equation of an electric field?
E = V / d
What are dielectrics?
Insulators placed between the plates of capacitor
What is the equation for C’?
C’ = k • C
Capacitors in parallel are added how?
Cp = C1 + C2 + … + C3
Capacitors in series are added how?
1 / Cp = 1 / C1 + 1 / C2 + … + 1 / C3
How is the electric field inside a metal?
0
What must there be for current to flow through a resistor?
There must be a potential difference
