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train45 (Bioengineer) (OP)
6 Feb 10 12:03
Hello all,

  I am a physician in the process of designing a new power handle for standard ophthalmoscopses (the instruments that are used to look at retinas).  As I know little about batteries, I was hoping somebody in this forum might help me with some basic questions:

All current ohthalmoscopes use two AA batteries for their power supply.  However, we are trying to design a very compact handle, and I was wondering if anybody had any suggestions as to how we could deliver the same power using a smaller battery (ies).  I would be willing to trade lifespan of the battery, but the power output would have to be the same, or the light would be too dim.  

For example, is there a way to use a single AA battery or even AAA battery (or two of these) to power the device?  Or is such a think impossible?

Thanks so much

IRstuff (Aerospace)
6 Feb 10 14:17
2 AAA's will provide the same VOLTAGE, about 3 volts, which is what you need to drive the light.  However, the battery life will be shortened.  There are button batteries that either singly or in tandem can provide 3 volts, but the smaller the volume, the lower the expected lifetime, given a fixed consumption.  

If you use LEDs for a light source, their power consumption could be lower, and smaller batteries mught have comparable life to your current system.


FAQ731-376: Forum Policies

itsmoked (Electrical)
6 Feb 10 15:20
There are many ways to skin this cat.

Is the scope a throw-away?  (A ridiculous wasteful trend that seems to be appearing in the medical industry.)

Are you trying to make the handle shorter in length or smaller in diameter?


Keith Cress
kcress -

IRstuff (Aerospace)
6 Feb 10 18:02
You can see some other battery choices here: You would need two 1.5-V batteries to get the 3 V that you probably need.  

Just bear in mind that these batteries will last less than 1/10 of the time that a AAA battery would last, in general.


FAQ731-376: Forum Policies

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