DIODE

PART - 1

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Diode look like –

And the symbols of diode are –

CONDUCTORS –

All Metals. Like - Silver, Gold. Cupper, Steel, Iron etc. Here we see the conduction band (C.B) and the valence band (V.B) is over lapping each other. For that reason, the electrons are easily move from V.B to C.B.

INSULATORS-

Rubber, Glass, Diamond, Wood, Plastic, Dry Paper etc. are the insulators, which can not carry the electron from V.B to C.V. Because the distance between V.B and C.V is grater then 5 electro volt (ev). This gap is called energy gap (Eg).

SEMI-CONDUCTORS-

Germanium and Silicon are the semi-conductors, because the Eg V.B and C.V is less then 5ev. So we can get the flow of electrons to applying some heat energy. Like-

In 0k temp.-

               Ge = 0.78ev  

               Si = 1.21ev

In 300k temp.-

               Ge = 0.72ev

               Si = 1.1ev

Those types of semi-conductors are called in-centric semi-conductor.

If we add some impurities with those in-centric semi-conductor to increase the speed of the flow of electrons then those elements are called ex-centric semi-conductor.

The process to create the ex-centric semi-conductor is called Doping.

Resistor's Color Coding

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We know,  V = IR from ohm's law

  Then, R = V/I

Ex. 

    If the voltage is 5 volt, and the current is 0.5 amps then what is the resistance across this source?

Ans. Hear we know the value of voltage and current. so we apply the ohms low, R =  V/I = 5/0.5 = 10 ohm(Ω).

[[Theoretically we can measure the value of resistance in presence of voltage and current. But we can find the value of any resistor through the color coding of this resistor, without any multi-meter.]] 

Hear we numbering some colors.

0 = Black, 1 = Brown, 2= Red, 3 = Orange, 4 = Yellow, 5 = Green, 6 = Blue, 7 = Violet, 8 = Gray, 9 = White. 

Hear we have a very easy trick to remember those color numbering. that is ""B B ROY Great Britain Very Good Wife.""

1st B = Black = 0

2nd B = Brown = 1

R = Red = 2

O = Orange = 3

Y = Yellow = 4

Great = Green = 5

Britain = Blue = 6

Very = Violet = 7

Good = Gray = 8

Wife = White = 9

Their have two many colors. Such are Gold and Silver. 

Golden = ±5% tolerance

Silver = ±10% tolerance

No color = ±20% tolerance

  In this above fig. we take the color strips from left side. So, the 1st color is Brown, then Black, Black and Golden. 

At first we take the 1st two strips and takes it's number.

Hear Brown = 1 and Black = 0, so, 10.

Then, the 3rd stripe, hear we get the '0' from this color numbering, that means

 0 = Black = nothing

 1 = Brown = 0

 2= Red = 00

 3 = Orange = 000

 4 = Yellow = 0000

 5 = Green = 00000

 6 = Blue = 000000

 7 = Violet = 0000000

 8 = Gray = 00000000

 9 = White = 00000000

10 = Golden = 1/10

11 = Silver = 1/100

Simply we add those '0' after 1st and 2nd conditions.

So, in our case we don't use any 0 to this number.

The 4th strip is golden in color, so, it indicates ±5% tolerance. 

So, the net result is 10Ω ±5%.

This ±5% tolerance means the value of this resistor  would be 9.5Ω to 10.5Ω.

Given resistors are only for you for practice. you can comment the answers in the comment below.

Learn About Resistance

From Ohm's law -
V/I = R 
V= IR
I = V/R

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RESISTANCE CONNECTIONS

1. SERIES CONNECTION

2. PARALLEL CONNECTION

SERIES CONNECTION-

From the upper diagram-

Here current I is same across all the resistances. 

We know,

V = V1+V2+V3

IR = IR1 + IR2 + IR3 [from Ohm's law]

So, R = R1+ R2 +R3

PARALLEL CONNECTION-

From upper diagram-

Here V is same across all resistance,

We know,

I = I1 + I2 + I3

V/R = V/R1 + V/R2 + V/R3 [from Ohm's law]

So, 1/R = 1/R1 + 1/R2 + 1/R3

1/R = (R2R3 + R1R3 + R1R2)/(R1R2R3)

R = (R1R2R3)/(R2R3 + R1R3 + R1R2)

So, G = G1 + G2 + G3

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BASIC OF CURRENT VOLTAGE ELECTRICITY

ATOM = ELECTRON + PROTON + NEUTRON

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Electron  = -1.602x10^-19

Neutron  = NIL

Proton    = +1.602x10⁺¹⁹ 

IONS = Positive and Negative 

Current-(I)  Controlled the movement of electron through a substance is called Current.
Direction of the flowing current is opposite direction of the flowing electron.

Electromotive Force-(EMF) EMF is the force that causes a current (I) of electricity to flow.
Total voltage in a electric circuit generate by the sources or battery.
It is applicable for electric field.

Potential Difference-(V) Work done per unit charge to more charge between the -ve and +ve terminal of the battery.
Potential Difference between 2 points in a circuit is electrical pressure or voltage required to drive the current between them.

It is applicable for magnetic, gravitational and electric field.

Resistance-(R) Opposition of flow of electron as well as the opposition of flow of current.

ρ = nature of material
l = length
A = cross section area
R = Resistance

Conductance-(G)

Conductivity-(σ)

OHM's Low-   For a fixed metal conductor, the temperature and other condition remaining constant the current (I) through it is proportional to the potential difference (V) between its end.

Relation between power, voltage and current-

P = Power

V = Voltage

I = current

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