Where to learn micro controllers and building amps

[stormrazer121]

As per title really, over the past few weeks I've digged pretty deep into micro controllers due to building my own portable rechargeable speaker (pretty good too ) But either way it has made me really curious about micro controllers, how they work and what they do as well as how to use one to build a simple amp, as well as re purposing items

So is there somewhere on here that i can read up and learn how to read the diagrams as well as where to learn the basics of micro controllers and how to wire them up (if possible a way to learn how to make my own that's something i would really like to do!)

Lucky for me i've been taking things apart since i was a young kid so I've always been into electronics/robots and how they work so I've got the patience and time to learn

So could anyone point me into the right direction? videos are good but im good at learning new stuff not only by watching videos but also reading and have always enjoyed an interesting read!

(past week I've ranked up over 20 hours worth of research on Li-ion battery's!)

cheers chaps

TLDR - i want to learn how to read diagrams and build a small amp for portable speakers

 

[audioguru]

You said you are building your own portable rechargeable speaker and say it is pretty good so maybe it is finished?
Then you said that you want to use a micro controller to build a simple amp?
But a simple amp does not use and does not need a micro controller. A simple amp is an IC or a few transistors.

A Li-Ion battery is fairly simple. It takes maybe 10 minutes to read about it at www.batteryuniversity.com .

You need to learn about the basics of electronics to read diagrams and build a small amp.

 

[stormrazer121]

Correct, i have finished my speaker dock, it was more of a learning curve and....i wasnt aware of battery university it wasn't just about learning how to wire one up i wanted to know everything so went deep into the background of them.

The reason i want to use a micro contoller is due to the amp i used (was from a old sony ericsson speaker) which has one on, and the others i have pulled apart all have them. i wasn't aware a simple amp was just an IC or a few transistors, would that mean i could make a simple amp which could provide power to my 3watt speakers in my next project?

This is where i am getting confused, i dont understand why all the small portable speakers i have all have a micro controller in them if you can have just a simple IC? wouldnt that make more sense to use or is there something that makes a micro controller better suited?

I'm going to google to understand the basics of electronics but if you could provide a decent source to read up on them that would be great also

 

[MrAl]

Hi,

The difference is probably in the type of amplifier. Linear amplifiers are like linear regulators, they eat up a lot of power that does not get delivered to the output. We could go through the math if you like. But a switching amplifier uses PWM to get much higher efficiency because it does not have to loose much power just to create a sine (or audio) signal because it creates a synthesized sine using pulses that are either on or off but no in between.

 

[audioguru]

A little arithmetic shows what power supply is needed for a speaker to produce 3W.

If the speaker is 8 ohms then the maximum RMS voltage into the speaker is [the root of (3W x 8 ohms)]= 4.9V RMS.
The maximum peak-to-peak output voltage is 4.9V x 2.828= 13.9Vp-p.
An audio amplifier output has a few volts of voltage loss so the power supply must be about 13.9V + 3V= 16.9V.

If the speaker is 4 ohms then the current in it is double the current in the 8 ohm speaker so the maximum peak-to-peak output voltage is half but the voltage loss is a little more.
The maximum RMS output voltage is [the root of (3W x 4 ohms)]= 3.5V RMS.
The maximum peak-to-peak output voltage is 3.5V x 2.828= 9.9V.
The voltage loss will be about 4V so the power supply must be about 9.9V/2 + 4V= 9V.

I have seen thousands of amplifier circuits but I have never seen one with a micro controller.

Here is the schematic of a simple audio amplifier that uses only 3 transistors. With a 9V supply and an 8 ohm speaker its output power is 0.9W. Its power can be higher with a higher supply voltage or a 4 ohm speaker but the transistors must be selected for higher currents.
Because it is simple its distortion is noticeable by some people.

 

[stormrazer121]

Yea see i don't understand all that just yet, i get what your saying but don't understand it. but something i'm guessing would helpo is this,

**broken link removed**

That's a photo of one of the amps I've been messing about with, it's stereo but from what i can gather has two "micro controllers" on it, at least that is what google and the images i have seen have told me, but from what you are saying suggests they are actually called ICs? am i correct or am i missing something?

Just so you know, one is called , 8002A MD1223Q the other is 8002A MD1227 see now they are what i assumed were micro controllers.

Also just to add these do power my 3watt speaker using a 2000mAh Li-ion battery, but i want to make my own and learn about them so i can say i made the whole thing and didn't just use a pre-built amp like with my first one. cheers BTW guys i must be getting on your nerves with all the questions XD

 

[Brevor]

Yes those are IC's probably preamps, or the amps themselves but they are not microcontrollers. All microcontrollers are IC's, But not all IC's are microcontrollers.

 

[stormrazer121]

Ah i see, hm so is a pre-amp really needed? if i can remove it from my design that would be great oh and i have gone and worked out how to read the diagrams so hopefully going to order some parts (when i know what i need exactly and build my first test prototype this weekend!