There is nothing inside a current dependent current source. It is not a physical entity. It is a mathematical device only. In this case, the collector current is dependent on the base current. The proportionality factor is beta, which is the transistor's current gain. I gave you the equation in a previous post, and a link to a more complete explanation.
The diode is there to represent the base-emitter junction, which has a forward voltage drop of ≈0.7V, but is actually a nonlinear function of base current

 

I will advise you to forget all this stuff about electrons, holes etc.

In electric circuit we are interest in a flow of a current. Just like a water flow in pipe the current flow in the wire. The force that cause the current to flow is a voltage or pressure in water analogy.

Voltage is present at a point or between two points, but voltage do not flow or move as current does.
So remember that voltage does not move; it is applied.

The current flow form "+" to "-", from higher potential to the lower potential, but in reality it doesn't matter which direction the current flows.
Because polarity of a voltage source doesn't change.

And of course the unit of current is Ampere [A] (Litre per second in water analogy).
And for voltage is Volt [V] (pascal [Pa] in water analogy).

The BJT work very similarly to the tap water valve.
A water valve is always used as a device to control the flow of water. Similarly, always think of a bipolar transistor as a device used to control electric current flow by assistance of a base current.
If base current (Ib) flows hen BJT is ON so there must flow β times Ib current through collector to emitter.
If Ib=0 then Ic=0 so BJT is cut-of.

http://forum.allaboutcircuits.com/showthread.php?p=165135#post165135

And don't bother your self with leakage current, you first need to understand the basic principles.

 

I will advise you to forget all this stuff about electrons, holes etc.

In electric circuit we are interest in a flow of a current. Just like a water flow in pipe the current flow in the wire. The force that cause the current to flow is a voltage or pressure in water analogy.

Voltage is present at a point or between two points, but voltage do not flow or move as current does.
So remember that voltage does not move; it is applied.

The current flow form "+" to "-", from higher potential to the lower potential, but in reality it doesn't matter which direction the current flows.
Because polarity of a voltage source doesn't change.

And of course the unit of current is Ampere [A] (Litre per second in water analogy).
And for voltage is Volt [V] (pascal [Pa] in water analogy).

The BJT work very similarly to the tap water valve.
A water valve is always used as a device to control the flow of water. Similarly, always think of a bipolar transistor as a device used to control electric current flow by assistance of a base current.
If base current (Ib) flows hen BJT is ON so there must flow β times Ib current through collector to emitter.
If Ib=0 then Ic=0 so BJT is cut-of.

http://forum.allaboutcircuits.com/showthread.php?p=165135#post165135

And don't bother your self with leakage current, you first need to understand the basic principles.

I understood the basic principles.
Now please explain on leakage current and minority current in terms of water analogy

 

Looks like a very crude Class-A amp, I wouldn't use it ;-)

Steve

 

Looks like a very crude Class-A amp, I wouldn't use it ;-)

Steve

It is also a thermometer. The trsnsistor fries the speaker more when it gets warmer.

 

I will advise you to forget all this stuff about electrons, holes etc.

In electric circuit we are interest in a flow of a current. Just like a water flow in pipe the current flow in the wire. The force that cause the current to flow is a voltage or pressure in water analogy.

Voltage is present at a point or between two points, but voltage do not flow or move as current does.
So remember that voltage does not move; it is applied.

The current flow form "+" to "-", from higher potential to the lower potential, but in reality it doesn't matter which direction the current flows.
Because polarity of a voltage source doesn't change.

And of course the unit of current is Ampere [A] (Litre per second in water analogy).
And for voltage is Volt [V] (pascal [Pa] in water analogy).

The BJT work very similarly to the tap water valve.
A water valve is always used as a device to control the flow of water. Similarly, always think of a bipolar transistor as a device used to control electric current flow by assistance of a base current.
If base current (Ib) flows hen BJT is ON so there must flow β times Ib current through collector to emitter.
If Ib=0 then Ic=0 so BJT is cut-of.

http://forum.allaboutcircuits.com/showthread.php?p=165135#post165135

And don't bother your self with leakage current, you first need to understand the basic principles.

You have stated that polarity of voltage source does not change.
What is the meaning of that. Also why is that we define potential with respect to positive charge and why is that we dont define with negative charge. Its not wrong to say that work done in moving unit negative charge against the force of repulsion as electric potential energy.If you consider negative charges then you wont ground the negative terminal but instead the positive terminal and consider it as 0 and negative terminal as 1.5 V say.

Also voltage drop is decrease in energy of unit charge. But in practise more than 1 unit charge flows say for 3 A current 3 unit charges flows. THat means total drop in energy is not voltage, its 3 times the voltage. If that is the case then still why do we talk only of drop in energy of unit charge i.e voltage drop.

 

You have stated that polarity of voltage source does not change.
What is the meaning of that

My point was that, it doesn't matter if you start analysis the circuit with
conventional current flow or electron flow. Because no matter with convention you choose the voltage across resistor don't change the polarity.

The voltage is a potential difference, for example if we have on one end of a wire 300 electron missing and on the other end 500 electrons are missing.
Then we have the voltage between the two points.
Both these "points" are positive, but the first point (300 electrons missing) is negative with respect to the second point (500 missing electrons).
So everything is relative.
And if we connect these points with a conductive wire then current is star to flow. From more negative point to more positive point. And current will flow until the number of electrons on both ends will be equal.
Voltage also inform us how many energy (in Joules) is transfer by every coulomb (current is a Q/t) in a wire.