Reducing Hiss in LM 386 Amplifier. Design Note 12


LM 386 is a popular 8 pin IC used as Audio Amplifier in hobby circuits. It is very handy and requires only a few components to make it as an Amplifier. Its output gives sufficient sound through an 8 Ohm speaker. But one problem during its working is unnecessary hissing sound through the speaker. This hissing sound becomes a nuisance in the standby state if the amplifier is gainy and the signal level is low. But we can eliminate this hissing noise by slightly modifying the circuit design.
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Tuning free AM Receiver. Design Trick 12

You can hear a local AM station clearly with this IC radio. It is tuning free so only the strongest nearby station will be available. Only a few components are necessary to build this Matchbox size radio and can be assembled quickly on a common PCB. No coil, No Gang, No professional touch. But still it is a Radio. See the trick to use the Gain pins of an amplifier IC as Signal receiver.
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Mobile phone Amplifier. Design Trick 7

You can use this Mini amplifier to hear music from Mobile phone or Laptop. The speaker of Mobile phone and Laptop is too small and the output voice is sharp with high tone which is not pleasant to hear music for long time. This circuit will solve the problem. It can be connected to the earphone socket of Mobile phone or Laptop. It is too small and portable. IC LM386 is used in the circuit which is  a low voltage audio amplifier IC and its gain is internally set to 20.
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