thebugger

modified 11 years ago

Low input amplifier

344

04:37:13

Under 10uV input over 2V output. Over 100000 times gain. For this amp to work one will need a few very low noise transistors (bc550) a very nice shielding and grounding too. Since every stage acts as a demodulator the whole circuit is not only an amp but also a detector too. Just add an LC bandpass filter at the input to tune in to different stations. The inductor should be 60-80 turns on a 10cm ferrite rod so it could become an antenna for the whole circuit. So basically this is an AM radio rather than a simple amp. Come on herzy find the flaws or better yet rebuild the circuit :D

published 11 years ago

hurz

11 years ago

We, Sec and I, gave you already some comments on this. You picked them up, and turned by mirical disadvatages into advatages. I have the feeling this circuit is just in your head and was never build in real. Keep on dreaming.

hurz

11 years ago

Its ok to publish circuits you dream of. But whats not ok is, you are writing your description to let others know you did that in real and you give advice how to do it in detail. I just dont like this. But if it makes you happy, it cant do anything against it, i can just give my 2 cents for this.

stefanoyoyo

11 years ago

Why can't I amplify the output pic current with a bjt BC107 so that I can handle a motor? With a tester I saw a 300mv when linking the bjt's base.

thebugger

11 years ago

Why do you wanna drive a motor in tact with an AM transmission. A garage door opener or what. Usually you can take the output and run it through an H bridge and drive your motor. But you'll need some sort of a transmitter too this is just a receiver.

thebugger

11 years ago

Quote me EXACTLY where I said I built this. You cant can you? Thats because you're only looking to find a flaw or something in someone else's circuit. Thats pathetic man! Buckle up!!!

hurz

11 years ago

And don't forget to use ultra low noise BC550. Ridiculous

faceblast

11 years ago

build it using 2N3055

thebugger

11 years ago

Well not really because amplifiing 10uV is pretty precise. The slightest noise may be stronger than the useful signal. Are you writing on automatic or are you just gasping on straws to pick a fight? Tell me already cuz I am getting pretty fed up from your pesky 'lil comments!!!!!

thebugger

11 years ago

2n3055 is a very old transistor and has a very low gain (min:10) and is quite noisy so its not the wisest choice. Plus there is no need for such powerful transistors. They will hardly dissipate any heat. I stand by my claim that bc550 will be the best choice due to their low noise properties and high gain (min:150 I think it was).

hurz

11 years ago

Forget any transistor and check how much noise you get for free from your 330kOhm resistor at input stage. Troll

thebugger

11 years ago

Yeah its enough isn't it. No need to add more noise from transistors bad shielding etc. Its common knowledge to all that certain rules must be kept at high frequencies (the highest frequency being exactly at the input) like close spacing between elements (to minimize parasitic influence) and good shielding and as good transistors with high gain you can find. I really dont see your problem with the bc550. Im just stating my opinion for the reasonable choice. But there you go again snapping like a crazy person off his medication :x

hurz

11 years ago

It will be your secret why you have to publish this circuit and for what reason. Keep on neurotic

thebugger

11 years ago

Oh so now you're implying only your circuits are worth. I will post whatever whenever I want without having to justify anything to you or anyone else! Next time you see something that's disturbing your shallow mind just keep it to yourself! I do NOT want your opinion neither do many others.

hurz

11 years ago

King buggzy, thats ok for me.

thebugger

11 years ago

And also try to write more literate when commenting. I wont overtax my brain just to understand your unwanted opinion.

hurz

11 years ago

Yes Sir!

rbrtkurtz

11 years ago

You guys do know that no one wins a fight on the internet, right? It's like fighting a homeless person. Even if you win, you still look like an asshole.

faceblast

11 years ago

Internet Men

faceblast

11 years ago

I built this circuit and it detects conversations from space and I used National Semiconductor D1618 epitaxial transistors because they have really short legs which makes them less likely to pick up noise! also I used broken pencils instead of resistors sorry

rbrtkurtz

11 years ago

http://www.mouser.com/ds/2/196/ds_fz3600r12ke3_3_1_de-en-92712.pdf 4700A IGBTs, and various cuts of pork for resistors. Suck it.

faceblast

11 years ago

HAHA

faceblast

11 years ago

can I have 300 ohms of sirloin, thanks

hamilton1300

11 years ago

Perhaps a nice thick slice of bacon could be used in place of a light bulb. I'm sure the resistance would increase as it heated up and the aroma would be a nice touch for any work station.

thebugger

11 years ago

Are y'all insane. You turned this into a dinner. You like to have the bacon though

hamilton1300

11 years ago

Everyone likes bacon

Sine_eyed

11 years ago

I talked it over with all the voices in my head and a consensus has been reached: we heart bacon..

hamilton1300

11 years ago

Then the voices in your head have demonstrated a high degree of cognitive development and you are wise to seek their cancel on matters in the future.

Sine_eyed

11 years ago

Funny, that's what they said too! X^)

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