need help, broadcast band RF AMPLIFIER

[ilyhen]

hi all, i m from indonesia and technical high school student.i got a task from my teacher to find an electronic circuit and presentation it in front of the class.
now i got a circuit from this link

**broken link removed**

can anybody help me to explain this ciruit,please:
1. what the function for each components
2. currents flow from this circuits
3. what is the concept about the circuit
4. why Q1 using FET.
5. what the functions of Q2 and Q3


i m realy grateful if u can answer my questions
please, teach me for the circuits

thanks in advance

 

[zachtheterrible]

The reason for using a FET is that it has a high input impedance, and is therefore a good choice for amplifying weak signals.

I would explain the rest of the circuit, but there is a pretty good explanation already. I think that you need to grasp other concepts before you can understand this circuit.

 

[audioguru]

You selected a circuit that uses transistors but you don't know how transistors work.
Instead, select a circuit that uses something that you know something about, like a lightswitch.

 

[mstechca]

Instead, select a circuit that uses something that you know something about, like a lightswitch.

can anybody help me to explain this ciruit, please:
1. what the function for each components
2. currents flow from this circuits
3. what is the concept about the circuit
4. why Q1 using FET.
5. what the functions of Q2 and Q3

What do you already know about it?
If nothing, then go simple.

Audioguru is on the right track, BUT I must admit, a light switch alone with nothing else (no battery, no light, etc) for a presentation will most likely give you a failing grade.

How about making a simple light bulb circuit.
Connect a battery, a lamp, and a resistor in series. (in a loop).
Experiment with all three components, and then you will definitely learn something.