Introduction: Mini Speaker

Picture of Mini Speaker

Today I'm going to make a mini speaker for Mobile or Laptop.... This project is for one of my friend on Instructables. Whose name is Verticees...

So, Let's Start...

Step 1: Requirements

Picture of Requirements

Items required

LM386

220uf 16V Capacitor

Potentiometer 10k

8 Ohm Speaker (If you have two 4 Ohms 3W Speaker. Then use in series to add the Ohms)

Power Source or 5 Battery

That's all

Step 2: What Is LM386

Picture of What Is LM386

It is a Low Voltage Audio Power Amplifier.

The LM386 is a power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from 20 to 200. The inputs are ground referenced while the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 milliwatts when operating from a 6 volt supply, making the LM386 ideal for battery operation.

Step 3: What Is Gain

GAIN CONTROL

To make the LM386 a more versatile amplifier, two pins (1 and 8) are provided for gain control. With pins 1 and 8 open the 1.35 kΩ resistor sets the gain at 20 (26 dB). If a capacitor is put from pin 1 to 8, bypassing the 1.35 kΩ resistor, the gain will go up to 200 (46 dB). If a resistor is placed in series with the capacitor, the gain can be set to any value from 20 to 200. Gain control can also be done by capacitively coupling a resistor (or FET) from pin 1 to ground.

Additional external components can be placed in parallel
with the internal feedback resistors to tailor the gain and frequency response for individual applications. For example, we can compensate poor speaker bass response by frequency shaping the feedback path. This is done with a series RC from pin 1 to 5 (paralleling the internal 15 kΩ resistor). For 6 dB effective bass boost: R . 15 kΩ, the lowest value for good stable operation is R = 10 kΩ if pin 8 is open. If pins 1 and 8 are bypassed then R as low as 2 kΩ can be used. This restriction is because the amplifier is only compensated for closed-loop gains greater than 9.

INPUT BIASING
The schematic shows that both inputs are biased to ground with a 50 kΩ resistor. The base current of the input transistors is about 250 nA, so the inputs are at about 12.5 mV when left open. If the dc source resistance driving the LM386 is higher than 250 kΩ it will contribute very little additional offset (about 2.5 mV at the input, 50 mV at the output). If the dc source resistance is less than 10 kΩ, then shorting the unused input to ground will keep the offset low (about 2.5 mV at the input, 50 mV at the output). For dc source resistances between these values we can eliminate excess offset by putting a resistor from the unused input to ground, equal in value to the dc source resistance. Of course all offset problems are eliminated if the input is capacitively coupled.

When using the LM386 with higher gains (bypassing the 1.35 kΩ resistor between pins 1 and 8) it is necessary to bypass the unused input, preventing degradation of gain and possible instabilities. This is done with a 0.1 µF capacitor or a short to ground depending on the dc source resistance on the driven input

Step 4: Long Description Make It Short and Simple

Picture of Long Description Make It Short and Simple

If you don't want to go through the above steps then do one thing just follow this step..

place all components as like this picture then solder it on PCB Board. And now put all these in a box/ old mini speaker contaionr....

Step 5: Some More Effective Circuits

Picture of Some More Effective Circuits

If you want to make your speaker more powerful then choose one of these circuits and if you can't understand any circuit then comment below and i will tell full description about that circuits

Step 6: Demo! Which I Made

Picture of Demo! Which I Made

Hope you Like It

If you have any problem related with it then comment below.

Thanks

Comments

Devin_Roberts (author)2015-03-05

I have read over how to make your speaker, and am finding it to be slightly confusing.

Tech Works (author)Devin_Roberts2016-02-03

Sorry for the confusion and too late response.

So tell me what's the matter

Tech Works (author)Devin_Roberts2016-02-03

Sorry for the confusion and too late response.

So tell me what's the matter

comicguru1 (author)2015-03-06

This is a cool and swift circuit! But may I suggest that if you short 1and8 with about 10mf capacitor i.e, the gain: you will attain a much higher volume!

Tech Works (author)comicguru12015-03-06

As you can see bread board circuit i used two capacitor one of then is shorted between 1 and 8...... It's really sounds nice but i don't need this speaker permanently that's why i used only one capacitor.... You can use that capacitor if you want to use it permanently

tomatoskins (author)2015-03-05

I build a little speaker system a few years back. It ran off 8 NiCd batteries. They later almost caught of fire. But it was a great little system for many years!

Tech Works (author)tomatoskins2015-03-05

I used a Male USB port which gives 5V regularly...

comicguru1 (author)Tech Works2015-03-06

I also use USB for quick power source!

About This Instructable

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Bio: I have some interest in electronic. you can find me at https://www.facebook.com/theTechWorks
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