Unit 2- Electricty Flashcards
What is direct current
D.C
Is the drift of electrons in one direction only
What is alternating current
A.C
The direction of the drift of velocity reverses, usually many times per second
What is a oscilloscope used for
It is used to measure frequency of an A.C supply
How do you calculate the peak voltage
Vpeak= square root of 2 x Vrms
What is emf
The electromotive force is the energy supplied to each coulomb of charge passing through an electrical supply
What is internal resistance
When a power supply is part of a closed circuit, it must itself be a conductor. All conductors have some resistance. A power supply has internal resistance of r
What is capacitance
The capacitance of a capacitor is therefore the charge stored per unit potential difference across the capacitor
How to calculate capacitance
C=Q/V
C= capacitance in F (Farads) Q= Charge In C (in coulombs) V= Volts In V
What is one farad equal too
One farad therefore is equivalent to one coulomb per volt
The voltage across components in what combines to give supply voltage
The voltage across components in a series circuit combine to give supply voltage
Voltage across the braches of what is the same
The voltage across a parallel circuit is the same
What is the current in a series circuit at all points
The current in a series circuit is the same at all points
Explain the current in a parallel circuit
The current in a parallel circuit beaches combine to give the current from the supply
What connection do AC and DC have
AC is equivalent of a DC supply known as ems value
What is a conductor
A conductor is component that allows electrons to move relatively easily
What is an insulator
An insulator does not allow elections to move easily
What is a semi conductor
A semiconductor can act as a conductor or insulator under certain conditions
What is a conduction band
A conduction band is the highest energy level.
How does conduction take place in the conduction band
I’m order for conduction to take place there must be electrons in this band
What is a valence band
A valence band is the energy level below a conduction band. Because the band is full it does not allow movement of charge
I’m a conductor describe conduction and valence bands
Conduction and valence bands overlap in a conductor. The conduction band is not filed therefore there is space for electrons to move from valence band
In terms of an insulator describe what happens to valence and conduction bands
The gap between bands is so large electrons cannot cross. The conduction band is empty while the valence is full
Describe the valence and conduction bands in a semiconductor
The valence band is full, the band gap is small enough at room temperature for some electrons to pass to the conduction band. More electrons+ More energy= more electrons can pass to conduction band
What group is used for P-Type doping
Group 3 atoms
