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Wire Kit for Battery

bubbagump00

May 24, 2010
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Can anyone tell me how to wire this kit for battery use? (Please don't say read the PDF data sheet. Trust me, I have.) I would like to use 3 AAA batteries.
 

LTX71CM

May 23, 2010
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You can't use 3 AAA batteries unless you modify that circuit. A 7805 needs more than five volts on it's input to maintain 5v on it's output. Couple that fact with the diode protection on the power jack and 4.5v from 3 AAAs just won't cut it. With the regulator in place you *might* get the circuit to function with 4 AAA batteries but don't count on it.

Assuming you provide enough batteries to satisfy but current draw and needed voltage it's as easy as wiring a plug to the battery holder. You of course need to make sure the polarity is correct and that the plug matches the jack on the board.
 

bubbagump00

May 24, 2010
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Okay. Well say I just bypassed the 5V regulator as it says in the data sheet for the kit, then would the circuit work? Or do I need to removed the diode D2 as well?
 

Laplace

Apr 4, 2010
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Diode D2 is only there to provide reverse polarity protection. What are the chances that you will insert the batteries in the wrong direction? If you were only using 2 cells, then it might be necessary to eliminate the voltage drop across D2. But with 3 cells there should be enough margin to keep D2 and still have IC1 work well.
 

LTX71CM

May 23, 2010
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I gave the circuit in the PDF a cursory glance and based on that 3 AAA may work. The ISD17120 datasheet does say it can operate from 2.5v-5.5v. If you bypass/remove the protection diode make very certain you've observed plug polarity.
 

bubbagump00

May 24, 2010
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Heres what I've got right now, and it isn't working: The positive lead is on X2, the negative on the other DC input hole.
Regulator is bypassed with a wire jumping the two outside holes together, the middle is left untouched.
Also, I removed the LED because I was unsure of polarity and simply bridged it with a wire.
Anything wrong with that? Why might it not be working?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Heres what I've got right now, and it isn't working: The positive lead is on X2, the negative on the other DC input hole.
Regulator is bypassed with a wire jumping the two outside holes together, the middle is left untouched.
Also, I removed the LED because I was unsure of polarity and simply bridged it with a wire.
Anything wrong with that? Why might it not be working?

Who knows?

Put the LED back in -- it should glow (I guess) when power is applied.

Ensure you have the correct polarity. One way is to measure continuity from the +ve supply pin of the IC to the connector that would connect to the +ve end of the battery.

Measure the current drawn, what is it?

What voltage appears across the supply pins of the IC?

edit: Why shouldn't we ask you to read the PDF? It's the first thing I did.
 
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davenn

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Sep 5, 2009
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bubbagump,
if you had read the pdf file you would fid that the chip needs 5V to operate !! No oneder yours isnt working if youa re only using 3 batteries there just aint enough voltage

the input voltage to the regulator is suggested to be ~ 9 - 12VDC (would work with 8 - 10V). ignoring the regulator you still need a MINIMUM of 5V for the cct to work

cheers
Dave

follow the rules .... READ THE INSTRUCTIONS :)

You NEED the LED it tells you when you are in record or playback mode DONT leave it out :)
 
Last edited:

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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the chip needs 5V to operate !! No oneder yours isnt working if youa re only using 3 batteries there just aint enough voltage

The specs for the chip suggest "2.4V to 5.5V operating voltage".

That's why I was concentrating on reverse polarity, accidental short or open circuit rather than on the < 5V supplied.

It's possible it required more current than AAA cells can provide, but I'd not consider that likely.

Since it's a kit, you've also got to wonder whether it was constructed correctly. Did it (for example) work correctly from (say) 9V before the modifications were commenced?
 

davenn

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Sep 5, 2009
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The specs for the chip suggest "2.4V to 5.5V operating voltage".?
That's why I was concentrating on reverse polarity, accidental short or open circuit rather than on the < 5V supplied.?

Yup Fair comment :)

Since it's a kit, you've also got to wonder whether it was constructed correctly. Did it (for example) work correctly from (say) 9V before the modifications were commenced?

Ahhhh thats the $6million question .... bubbagump ... did you try it on 9V before you started bridging out components ? if not it would probably be a great idea to get it working in its originally designed way :)

Dave
 
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