amplifier which can amplify what we speak

[anuphr]

i want an amplifier which can amplify what we speak and give it out through a speaker (8ohm).. i have rigged up 1 using lm386 but it is not working fine.. it just gives me a lot of noise....i am giving input through a small mic..
i am very confused plzz do hepl me i have to submit this project to my college in other 2 days ...
if u have any circuit plzz give it...
plzz do help me,it will be of great use.

 

[pranam77]

Noise is the problem with the hardware and not with the chips you use. Basically using LM386 or any general purpose amplifier output stage connected to a microphone pre-amplifier stage should work fine. Have a look at the project in the given link. I think thaz the one you are looking for. Hope it helps you. Do not forget the "helped me" Button. Cheers.
**broken link removed**

 

[anuphr]

using lm386

thanx for that. can i easily get that ic. is there any circuit using lm386,bc547...\
it will be of very use.. plzz . can i use a mic as input,speaker 8ohm as output..
im using lm386 for audio amplificatiion.but it is not working..wat to do wat might be the problem

 

[pranam77]

Yes..the BEL1895 is a popular audio amp which was used in radios. It will be available with any component dealers arround.
The given circuit is perfect and shud work provided the used components are good. I have personally used LM386 in many of my designs without any problems.

 

[anuphr]

can u just post me any circuit of lm386 amplifier.. plzz
the circuit is not giving any output...but it is not giving noise too...

Added after 12 minutes:

this circuit i have used of 386 is not working can u tell me waty may b the reasons

 

[hock]

keep your microphone shielded, use shielded cable from microphone to opamp.
hock

 

[anuphr]

ya the microphone is sheilded .... it must be connected to the -ve end of 1uf and ground... the wires of the mic is sheilded


is this circuit correct will it work ..............

 

[pranam77]

You may try this schematic from the datasheet, with modifications of Pin 2 used as Input. If this doesnt work, upload a clear Photos of the Component side and the trach side of your assembled baord. I strongly doubt something wrong in your assembling or hardware part. Cheers

 

[anuphr]

ill just check it ..all the circuit connections are correct...can i use a polar capacitor instead of a non polar one...

 

[pranam77]

can i use a polar capacitor instead of a non polar one...

Which capacitor are u refering to? Probably all components are available with Hobbby component dealers. Cheers

 

[Audioguru]

The first LM386 amplifier circuit is from me. It works perfectly.
Describe what noises it makes. Hum?
did you use a two-wires electret microphone connected with the correct polarity with shielded audio cable?

Oh. "A lot of noise" is probably acoustical feedback howling. Separate the microphone and the speaker between two rooms with the doors closed.