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kevin11

Sep 11, 2010
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I found this site that seems quite interesting ( www.project-world.co.cc ) but wanted to know if i build any of the projects on this site will they really work?

has anyone built any of them before? are they any good?
 

kevin11

Sep 11, 2010
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p.s, let me know if you have any better schematics that do the same thing
 

Resqueline

Jul 31, 2009
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They'll work, even if a few are a bit simple in their design. Most of the circuit descriptions leaves something to be desired though.
 

kevin11

Sep 11, 2010
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Yeah, i was looking around for ages trying to find good audio amp projects and the schematics on that site seemed easy enough for me to build.

i just wandered it it would really work, last thing i want to do is buy parts, spend time, get burnt (lol) and then it not work.

thanks for the reply :)
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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The first one I looked at. What is the point of R1?

Seems to me that all it does is put a DC bias on the input which could may be fine for an electret microphone, but not for much else.

The second thing I looked at was a "body heat detector", a non-trivial circuit. The download link for the schematic and parts list contains only a GIF image in a zip file. The GIF image has the schematic, no parts list and an entire paragraph explaining what the circuit does. I found no further explanation.

From what I saw, very unimpressive.
 

kevin11

Sep 11, 2010
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Tomorrow im gonna buy the parts to make This headphone amp (make my first project a simple one :p ) but i might also build that one too this and see what happens if i leave out R1.

:-D im all excited to see what happns
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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I'd encourage you to find the original source for these circuits.

The headphone amp apparently comes from http://www.redcircuits.com and they provide a description of the circuit rather than just the schematic and list of parts.

edit: 9V Headphone Amplifier

I think it is pretty bad form to copy someone's work without even linking to the source.
 
Last edited:

kevin11

Sep 11, 2010
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Yeah, well i built the 9V headphone amplifier and it works quite well :) the battery gets a little hot after ten or so minuets but i guess thats to be expected.

http://www.redcircuits.com is on project-world.co.cc in the links part of the site... i just dont really understand what the point of the site really is seeing as the person who it was created for no longer wants it :-s.... i guess its up to prove a point to his mate or somthing.

im going to try and build a voltage multiplier so that i can run it off of 1 lithium AAA cell
 

kevin11

Sep 11, 2010
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Oh hey dose anyone know of an invertor kind of like this one that you can use with solar panels directly? i want to connect a small mains powed 6" tv to it. it only needs to be on between like 9am to 1pm because its connected to a CCTV camera thats over looking my car. also i was told it would need to be a "pure signwave" invertor too otherwise the tv wont work, why is that?
 

Mitchekj

Jan 24, 2010
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My first thought is that using a non sine wave inverter (like a square wave) may cause way too much input current to flow in the TV's power supply section. A nice slow ramp-up from a sine wave will generally keep the "inrush" currents each cycle to a designed limit, instead of the near instant 0-120/240 level of a square wave.

Other problems could be hold-up (of the DC bus voltage,) and any EMI filtering inductors/chokes would probably not be too happy with the sudden change in current either.

All speculation there. :)
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Yeah, well i built the 9V headphone amplifier and it works quite well :) the battery gets a little hot after ten or so minuets but i guess thats to be expected.

I certainly wouldn't expect that.

Batteries getting hot is a BAD sign.

A small 9V battery hasn't really got much energy stored in it, so it's not going to fail spectacularly. But it indicates way more current is being drawn from the battery than it is capable of easily supplying.

Measure the current. At the very best you'll get a short battery life.
 
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