Mod 4 Flashcards
How many electrons in the outer shell of a semi conductor?
3-5
What is the outer shell of an atom called?
Valance shell.
How many electrons in the outer shell of a conductor?
1-2
How many electrons in the outer shell of an insulator?
5-6
Meaning of forward biast?
Little resistance to current flow.
Meaning of reverse biast?
The diode has high resistance.
Explain N-type doping.
- Uses arsenic as dope.
- 5 electrons in outer shell.
- A donor impurity.
- 5th electron has nothing to bond too.
Explain P-type doping.
- Uses gallium as dope.
- 3 electrons in outer shell.
- A acceptor impurity.
- Missing electron forms holes.
Explain the construction of a silicon diode.
A silicone diode is built up of an anode and a cathode. The cathode being the N-type material and the anode being the P-type material. As a current is passed, the spare electrons from the cathode side travel to the absent holes in the N-type side allowing current to flow one way.
What is the ripple frequency of a full wave rectifier?
Double the supply frequency.
What is smoothing?
Smoothing uses the use of capacitors with diodes to produce a smooth output voltage. As the diode receives the first half wave whilst it is in forward biased, the capacitor charges. When the A/C current had it’s negative cycle, the diode changes to revere biased preventing. The capacitor now discharged into the loads causing a steady output voltage.
Diodes only allow current to flow in?
One direction.
Are diodes in these days solid state, liquid state or gas state?
Solid state.
Common semi conductor materials used in diodes are?
Silicon and germanium.
What is rectification?
Changing A/C to D/C.
