This is an audio amplifier that can use with a small 9 volt Battery Operated, Current use as little as 5 milliamps. And amplification up to 500 mW. Which is sufficient to expand the sound from a sound about or the CD Walk Man out to the small speakers clearly. When entering the power supply 9-volt circuit IC1 number LM386 amplifier IC size is 300-800 mW, Depending on the power supply circuit with, This is from 4-15 volts.
Figure 1 the LM386 mini audio amplifier circuit
Once entered into the input pin 3, The non-inverting pin to amplifier non-return phase.C1 will be served cut out the noise input to ground, and C2 increases the rate of the amplifier, C2 is to add more value.
But if the C2 Too much distortion (the C2 should not exceed 100uF).
The output of IC1 is out of the pin 5 through C4 coupling audio signals to better and DC block and not passed to the speaker.
For the audio portion will also be fed back through R2 and C3 to the high-frequency response better.
How to builds
This circuit, you can easily make it with see PCB layout and the components layout in Figure 2
Next circuit ideals that use LM386 IC.
LM386 mini amplifier
500 mW Power Amplifier using LM386N
This circuit number LM386 IC is used as the IC, which is popular is that it has. It is a simple circuit. Fewer equipment items. Suitable for use or used in small trials.
The properties of the IC can be used from the 4V-12V power supply for low current at 50 mA only. And the frequency response from 40Hz – 100 kHz rate of expansion of 46 dB and distortion.
Less than 1%.
When entering the power supply light LED1 circuit to tell the operating environment of the circuit. C6 and C7, with a page filter to smooth then be entered through one input sound signal.
C1 coupling signal protection dc voltage noise in the circuit to the sound signal that is transmitted through VR1 for controller level reputation of the sound signal and then sent to the input to pin 3 of IC1.
boost up output at pin 5 through C5 for protection dc voltage and meet the low frequency better and send output speakers. The C4 and R1 are acting eliminate noise signal out and the pin 1 of IC will have a jumper for. to access the C3 to boost up rate increase in case the circuit to be used to boost up signal is very small.
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