Circuits
By Levi Clancy for Student Reader on
updated
- Physics
- Calorimetrics
- Circuits
- Electricity and Magnetism
- Fluid Dynamics
- Fluid Statics
- Friction
- Human Eye
- Ideal Gas Law
- Interference and Diffraction
- Kinematics
- Mirrors and lenses
- Newton’s Law of Gravitation
- Newton’s laws of motion
- Optics
- Oscillations
- Physics of Breakdancing
- Polarization
- Power
- Thermal expansion
- Thermodynamic Systems
- Vectors
Magnetic field of a loop of wire: B = µ0 I / 2 R
Time rate of electric field on a capacitor: dE/dt = I / ( ε0 A )
(where A is the area of a capacitor plate)
Electric field between capacitor with a charge: E = Q / ( ε0 A )
For positive charges, F and E are opposite.
For negative charges, F and E are the same direction.
Potential energy between two charges: U = k q1 q2 / r122
Θ = qenclosed / ε0
For an infinite line: qenclosed = λ L and E = 2 k λ / r
For a sheet: E = ½ σ / ε0
For two plates: E = - V / d (ΔV between plates, divided by distance between plates)
For a circle: E = k q / r2
Cylindrical air coil: L (inductance) = µ0 N2 A / l
ΔV = I R = E d
ΔU = q ΔV for some test charge
Q = C V = ε0 A E
W = ΔU = - q ΔV
ΔV = ΔU / q = k q / r
℘ = I2 R = I ΔV = ΔV2 / R = I Ε
Ε = I R + I r (way to find epsilon when an external resistor is in the circuit)
R is external resistance, r is internal battery resistance
ΔV = Ε - I r
I = Ε / ( R + r)
Epsilon is EMF, the Delta V when no resistor is in place if you will, and delta V is the voltage difference when the resistor is connected.
Series | Parallel |
Diff ΔV | Same ΔV |
Same Q | Different Q |
Ctotal-1 = C1-1 + C2-1 | Ctotal = C1 + C2 |
Vtotal = V1 + V2 | V1 = V2 |
Rtotal = R1 + R2 | Rtotal-1 = R1-1 + R2-1 |
Itotal = I1 = I2 | I1 = Itotal ( Rtotal - R1 ) / Rtotal |