:shock:
wow!!!!!!!!!!!!!
now that is an achievement
hats off for you
i did O levels too
but didnt left schooll...did A levels too...now doing Electronics Engineering

4 yr course...

 

My teachers didn't have much to teach me about electronics, but I taught them a lot. :lol:

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Uncle $crooge

 

lolz
which uni or college?

 

Ryerson University in Toronto, Canada.

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Uncle $crooge

 

now am making this
and hav absolutely no idea what it is...other than that it is an amplifier

tell me...oh please tell me....is it Class A config or CLass B or what?
i am using an 8ohm .5watt speaker? is it enuff?

Attached Images

audioa13.gif (13.1 KB, 541 views)

 

It's class B or class AB, it's also a VERY poor design, for many reasons - but a 0.5W speaker would be fine.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Wow! You've found a very powerful audio power amp design.
I've done some numbers-crunching on it and I figure that it will give a whopping power into the speaker of 15.6mW.

You might hear something if you turn up the volume and hold the speaker directly to your ear. :lol: :lol:

Attached Images

audioa13_calculations.png (38.2 KB, 533 views)

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Uncle $crooge

 

I built this amp for my son's alarm clock. It has nearly 10 times the power of yours from its little 8-pins IC.

Attached Images

150mw_amp.png (18.4 KB, 524 views)

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Uncle $crooge

 

My 150mW amp has poor bass response.
Replace the 0.1uF cap in series with the 3k resistor at pin 4 with 4.7uF.
I have edited the schematic. :lol:

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Uncle $crooge

 

Isn't the internal circuit of the chip wrong as well?, the input is shown connected to the non-inverting input of BOTH amps.

I suspect there should be no connection there?, but a second 125K to the non-inverting input of the top amp.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

It works fairly well when the gain is high. The 1st amp has a gain of 26, and the 2nd amp has a gain of only 24 which isn't too bad a difference.
If the gain was only 1 then the 2nd amp wouldn't have any output.
Actually, with a gain of one then the output of the 2nd amp would be only the distortion products of the 1st amp.

The amp can be setup with an inverting input and with a low input impedance. Then the output level from each amp is the same.

I don't like the 2nd amp amplifying the distortion from the 1st amp, but it sounds OK with its very high amount of negative feedback cancelling the distortion. :lol:

__________________
Uncle $crooge

 

You appear to have missed the point?, as drawn the inrenal circuit wouldn't work - the input is applied to BOTH non-inverting inputs, so the outputs will be in phase, so no sound at all from the bridged speaker.

I'm also pretty sure no body would design a bridged IC with different gain values, presumably another mistake on the diagram?.

It doesn't matter much when it's done that way, because the distortion is reduced by the attenuation factor corresponding to the gain of the second amplifier.

Sorry, just looked back at the circuit, it's not done that way, the second amp is just a unity gain inverter - so the non-inverting inputs definitely shouldn't be connected!.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

stop making fun of it...
am already so dishearted...
i was making a power amplifier 80 watts!!!!!!
and here i am...making this crap
but i have to submit it day after tomorrow..and am fasting...and tomorrow is friday so all shops will be closed
so i AM sticking to this design...

but atleast my teacher will b happy to see so many capacitors and transistor...am telling you guys...he knws NOTHING...he even told us tht when u supply DC voltage to a capacitor....the circuit becomes short :shock: ..and i thght it behaaved as an open circuit :lol:

and the best part..."if the resistance on emitter is grounded....there will be no voltage drop across it"
lolz

 

Hee, hee. :lol: Stick it on a simulator that works, and you'll see the 1st amp with a gain of 26 and the 2nd amp out-of-phase with a gain of 24. :lol:

Motorola did.

{quote]the second amp is just a unity gain inverter - so the non-inverting inputs definitely shouldn't be connected!.[/quote]
When configured as an inverting amp, the non-inverting inputs are bypassed to ground.

Attached Images

150mw_amp-inverting.png (18.2 KB, 503 views)

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Uncle $crooge

 

Just trying to delete my duplicated post.

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Uncle $crooge