LM386 Audio Amplifier Chip

Posted on Feb 5, 2014

Terminals 1 and 8 represent the gain control of the amplifier. These are the terminals where you can adjust the gain by placing a resistor and capacitor or just capacitor between these terminals. In this circuit, we will place a 10G‚ µF capacitor between these terminals for the highest voltage gain. Terminals 2 and 3 are the sound input signal ter

LM386 Audio Amplifier Chip
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minals. These are the terminals where you place the sound which you want to amplify. Terminal 2 is the -input and Terminal 3 is the +input. In our circuit, the positive sound signal will be placed on terminal 3 and terminal 2 will be tied to ground. Terminal 7 is the Bypass terminal. This can bypass 15KG resistors. This pin is usually left open or is wired to ground. However, for better stability, a capacitor is added in our circuit because this can prevent oscillations in the op amp chip. C1 is a capacitor that is used to set the gain of the op amp. By placing a capacitor here, we can set the gain to the highest level to get maximum gain, which in this case is 200. Therefore, the voltage coming out of the op amp is 200 times the voltage going in. C2 is a smoothing capacitor. If the power supply has any abrupt voltage or current spikes, this capacitor works to smooth out the signal so that it evens out those spikes. This capacitor helps to eliminate all of those ripples, which translates to the op amp having less noise input into it. C3 acts as a current bank for the output. This capacitor fills with electrons when demand for current is low and drains when sudden surges of current occur. The LM386 amplifies the sound input into it by a factor of 200. All amplifiers need DC voltage in order to run. The LM386 takes anywhere from 4-12 volts of DC voltage to operate. The sound signal to be amplified are placed on terminals 2...

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