Electricity Flashcards
what is the rms value
Measure of the real effect of the signal
What is the peak value
measured from the 0 point to the highest current/voltage of the wave
Calculating peak value or rms
Vᵣₘₛ=Vₚₑₐₖ/√2 Or Iᵣₘₛ=Iₚₑₐₖ/√2
Finding period or frequency
T=1/f
Emf & Potential Difference
Emf- Energy transferred to electrons e.g. Voltage from power source
PD- Energy transferred from electrons to components e.g. Voltage on resistors
What is AC
Current which changes direction and instantaneous value with time
Why are volts lost in a circuit
internal resistance
Finding emf lost volts or terminal potential difference
E=V+Ir
1 Farad=
1 coulomb of charge when PD is 1V
Capacitance
C=Q/V or Q=It
As a capacitor charges
Current decreases till it stops flowing
PD increases till it reaches emf
Energy, Charge and Capacitance
E=1/2QV
Valence band
Outermost of the energy levels
Conduction Band
higher energy levels
Energy gap
Space between valence band and conduction band
Conductors
have overlapping or very close together bands & each band is partially filled
Semiconductors will conduct when
The electrons have enough energy to jump from the valence band to the conduction band
Doping is
Where an impurity is added to the semiconductor to increase conductivity
P-type Doping
have a missing electron
N-type Doping
Has an extra electron
Forward bias
Reduces electric field
Reverse bias
increases electric field
What is a p-n junction
A device with adjacent p & n type layers & a conduction band that prevents the flow of charge unless voltage is applied
Q=
Charge in Coulombs
T=
Period, time taken for one wave to pass (s)
x axis
y axis
X= Time Y= Voltage
