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Placement of batteries (button cells) in the same plane on two sides of PCB

at89atbits

Sep 20, 2014
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Hi,
In my design I need 4 batteries in total and hence I have placed two on one side of the PCB and two on the other side right below the first two.
Because rest of the circuit isn't too big and the batteries are eating up too much space.
But will that cause a problem in any way if the power signal traces are running parallel to each other on the two sides of the board?
Do I need to change the placement or this won't cause any substantial problem?
 

(*steve*)

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Jan 21, 2010
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I can't see there would be a problem.

But I'd probably put all the batteries on one side of the board.
 

KrisBlueNZ

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Nov 28, 2011
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I don't see any problems either, apart from difficulty accessing the cells to replace them.
 

shrtrnd

Jan 15, 2010
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I agree with *steve* and KrisBlueNZ.
I know you're concerned about the amount of space placing the batteries on one side of the board, but as a tech who has to work on boards designed by people like you, I appreciate it when the board construction
allows for easy access/replacement of batteries. Sooner or later that will need to be done. You might consider checking into the many different types of battery mounts. If space between boards allows, I've worked on
a lot of instruments where the battery mount is raised up off of the board, allowing for circuitry underneath the mount. (So board space is not impacted as much).
 

BobK

Jan 5, 2010
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The question I would ask is why you need 4 batteries?

Bob
 

Gryd3

Jun 25, 2014
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The question I would ask is why you need 4 batteries?

Bob
I second this question...
Series or Parallel?
You can get battery holders for button cells that hold more than one battery. (They get stacked)
 

at89atbits

Sep 20, 2014
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The question I would ask is why you need 4 batteries?

Bob

I am using opamps with dual rail supply
Opamp needs +- 6V.
And my microcontroller needs +3.3V
So I need four 3V batteries for generating these voltages.
Is there any other way I can generate these voltages on the board?
 

BobK

Jan 5, 2010
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There are opamps that will operate from a single supply of 3V. How are you using them, do you need the whole 12V range?

Bob
 

at89atbits

Sep 20, 2014
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Hi Bob,
Yes I need the entire 12 V range
I am using LM386 which needs a single supply of 6V and ground
and I am using LM741 which needs dual rail supply of +6V and -6V.
Also I am using a microcontroller which needs 3V.
So for generating these different voltage values I am using four 3V cells.
 

davenn

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The 741 is a VERY old Op-Amp
There are much newer and lower noise ones these days
it would be worth you considering a change :)
 

BobK

Jan 5, 2010
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I understand that the opamps you have chosen may require + and - 6V, but that is not what I was asking.

The real question is whether the signals they are processing need to be in that range. Because if all of the signals can be confined to 0 to 3V, you can use 3V rail-to-rail opamps instead and get by with 1 battery. If you need + and - 3V your can get by with two batteries, or you can generate the - voltage from the + voltage with a buck-boost converter, which inverts the output voltage.

The '741 is an obsolete opamp that performs miserably compared to modern op amps.

Also did you know that with the 741 with + and - 6V, your outputs are going to be constrained to about + and - 3V?

And the LM386 can be replaced by bridge amplifiers that would match it's performance with 3V.

If you want any more help, you will have to tell us more about what you are trying to do. I just think that needing 4 batteries because you are using an obsolete op amp is not the optimal solution.


Bob
 
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