Transistor as audio amplifere's ......!!

[koolguy]

Hello again,


I want to make a amplifier using transistor, now it should have loud sound then earlier circuit given by Audio Guru and i don't want to add ready made chip in it....!!



Thanks

 

[ronv]

How about this one?

https://www.redcircuits.com/Page61.htm

 

[carbonzit]

... except that that amp uses an IC (op amp). Pretty good otherwise.

 

[koolguy]

I want to make circuit my self, testing it and biasing transistor ..!!

 

[carbonzit]

OK, so do you have anything you can give us? made any sketches on the backs of envelopes? any ideas?

How much power? how small? how many transistors? power supply voltage? drive a speaker? or headphones?

Give us something we can work with. We're not going to spoon-feed you.

 

[koolguy]

Hello sir,

I want to drive near by 12 inch speaker just for fun or less than this will also work....!!
I have no sketch of it. power supply of 12V or less than this will also work.

 

[koolguy]

Hello sir,

I want to drive near by 12 inch speaker just for fun or less than this will also work....!!
I have no sketch of it. power supply of 12V or less than this will also work.

 

[audioguru]

The extremely simple amplifier I posted will be loud only if you hold the speaker to your ear because its output power is very low at only 0.42W like a cheap clock radio. With a 12V supply the output will be a little more but then the small output transistors might melt.

The simple amplifier sounds pretty bad with about 10% distortion when it plays its loudest.

 

[koolguy]

Hello sir,

.......its output power is very low at only 0.42W like a cheap clock radio. With a 12V supply the output will be a little more but then the small output,...............

that's why now i want to learn how increase amplifier output power.....

 

[audioguru]

Your English is poor:
What is "learn more big one"?
What is "coupling of amplifiers"?

 

[koolguy]

OK, now please tell.........

 

[Ziddik]

how much output power do u expect from the amplifier you want to make?

 

[koolguy]

It should drive 12 inch woofer or less will also work, but there should not be any ready made amplifier chip used in it, it can have transistor transformers, darlington,......

 

[carbonzit]

You still haven't answered the question. "12-inch speaker" tells us nothing.

Do you want to drive it at 1 watt? 10 watts? 100 milliwatts?

 

[audioguru]

You are in school (University?). Then ask your teacher to teach about how transistors work and how they can be used in a simple amplifier.

 

[koolguy]

Do you want to drive it at 1 watt? 10 watts? 100 milliwatts?

OK, 5-7 watt amplifier.

 

[audioguru]

OK, 5-7 watt amplifier.

7W into 8 ohms is a voltage swing of 21.2V. A simple amplifier will have a peak to peak voltage loss of about 5V so the amplifier will need a supply of 26VDC. If you use a 4 ohm speaker then the supply must be 20VDC. If you use a 4 ohm speaker and make a bridged amplifier then the supply must be about 12.5VDC.

 

[koolguy]

Hello, AG how you have calculated the supply voltages?

 

[audioguru]

Hello, AG how you have calculated the supply voltages?

I used simple arithmatic.
A signal that is a sine-wave and produces 7W into 8 ohms has an RMS voltage of the root of ( 7 x 8)= 7.48V. Its peak-to-peak voltage is 7.48V x (2pi) which is 21.2V. A simple class-AB amplifier has about 5V of losses so the supply must be 21.2V + 5V= 26.2V.

I double-checked with the datasheets of two power amplifier ICs.

 

[OlPhart]

Howdy, I just CANNOT resist... are "we" Sure the OP Isn't an Eliza program ??

Sorry, I've just seen Way too many posts Not to sense the two year old childs' aspect... "Why is the sky blue..." ...... ad nausaem teehee... <<<)))

If this begats flame... rock & roll: those who know me well would be impressed at my tolerance.

P.S. I know denigrating posters is Really poor form, but this one's past the pale....