How to read power supply in a circuit ?

I am beginner to Electronics,
Can you tell me how to :
Read power supply in a circuit?
Test NPN & PNP transistor ?
Build a battery eleminator with a stable voltage supply(i.e. suppose I need 3.3v and want to get exactly 3.3v constantly)?
Build a FM Receiver with a minimum parts ?

Holy smokes, I don't think the Internet has enough bandwidth to provide you with all that long of a relpy!! Testing transistors is easily found on the web by using your browser... loads of sites that explain how and also provide simple circuits as go/no go testers. Reading a power supply diagram depends upon circuit complexity so that's difficult to do here without a specific example. Making a 3.3v supply using a 7805 regulator and padded from there is easy. FM receiver kits are available thru the web as well as schematics to build them. Minimal parts tho, well that depends on what's out there.

Honestly, I'm amazed at how many peeps are on this board ask us for the sun, moon, and stars when often the answers lie directly infront of them by simply spending a little time web browsing. I'm not bashing you, just trying to get you to put forth some effort on your own. It's called learning effort and the rewards are quite satisfying.

HiTech said:

I'm not bashing you, just trying to get you to put forth some effort on your own. It's called learning effort and the rewards are quite satisfying.

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It looks a lot like homework to me. Its not like its hard to type "transistor test multimeter" into google and find some simple on your own.

I hear ya! I'm OK with assisting a poster that has a legitimate request, who displays evidence that he/she has undergone some effort in the process and has hit a wall needing some help, but to do their "homework" for them from start to finish is rediculous and this place seems to have plenty of those requests. Another member has already commented similarly about newbies jumping in here asking for us to give them the sun, moon, and stars so they can receive an A on the project!!
I say the first step in advising them is to get them to change their diaper and walk upright!

Thank you Hitech & dboyer for reply !

When you say read power supply do you mean test the voltage? any multimeter will do that for you

HiTech said:

<snip>Making a 3.3v supply using a 7805 regulator and padded from there is easy.<snip>

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You can't make a regulated 3.3V supply that way. An LM317, a couple of resistors, and a couple of caps will work. Of course, you still need a source of unregulated DC, which can come from either a wall wart, or a transformer, rectifier, and filter capacitor.

Ron, of sourse I realize there are surrounding components required, but I have a schematic that does indeed use a +5v regulator. If I search thru my piles of papers, I might find it so I can post it.

HiTech said:

Ron, of sourse I realize there are surrounding components required, but I have a schematic that does indeed use a +5v regulator. If I search thru my piles of papers, I might find it so I can post it.

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When you find it, I'm betting it will also require a negative supply.

You could stick a resitor and a 3.3 V zener in the ouput of the 7805 but the variable Regulator is the better solution is it not.

To test a PNP and NPN transistor, most newer mulimeters have a little thingy on them to do the test for you.

Ron H said:

When you find it, I'm betting it will also require a negative supply.

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I was wondering if we add 3 diodes in series, on the 7805 output?
We gonna have a 2.4V drop there.

Or we can add a parallel 3V2 zener there.

I may be mistaken.

Hayato said:

I was wondering if we add 3 diodes in series, on the 7805 output?
We gonna have a 2.4V drop there.

Or we can add a parallel 3V2 zener there.

I may be mistaken.

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Either of those options is vastly inferior to an LM317 and a couple of resistors.