View Full Version : help needed regarding low voltage power amplifier

09-18-2010, 08:05 PM
i have made the circuit on breadboard n only hiss(noise) is there from speaker
pls help me n tell me where i was wrong

09-18-2010, 09:18 PM
Tough to tell whats wrong without a picture of your breadboard setup.
Please post a picture of your breadboard setup if possible.

09-19-2010, 01:07 PM
i will post my breadboard pic ,but i want to tell that i dont have 0.05mf n 10 ohm resister between pin 5 and 4 .is this the problem???

09-19-2010, 03:12 PM
What are you using in place of 0.05 mf capacitor ?

09-19-2010, 06:42 PM
i m using nothing ,is this wrong ?

09-21-2010, 11:40 PM
i m using nothing ,is this wrong ?

What else are you NOT using??
Hope you are using the Chip.

09-23-2010, 08:54 AM
First : READ the DATASHEET !!!
1. Increase the Mic resistance from 10k to 47k (Use a preset)
2. Change potentiometer from 100k to 10k.
3. change Mic coupling capacitor from 1uFd to 0.1uFd.
4. Output cap should not exceed 220uFd.

It is better to use a Mic pre-amp around a transistor like the BC549, rather than a direct connection to the 386.

What voltage are you using ?? When you say 'low voltage' what do you actually mean ? 9v is not exactly 'low' .

The circuit is working fine here- with all these combinations. if you still get hiss alone then change the Mic.

09-23-2010, 07:34 PM
What else are you NOT using??
Hope you are using the Chip.ha ha, allbits i have used the chip

thanks docel for this ,and im using 9v battery

09-25-2010, 10:31 PM
hey docel can u post ur breadboard picture