It's a self resetting fuse like device also there are ICs of the three
or even two legged types to monitor battery temperature.
Allison
-----Original Message-----
From: Richard Erlacher <richard_at_idcomm.com>
To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
Date: Friday, September 01, 2000 9:16 PM
Subject: Re: Ni-MH pack topology [semi-OT, I know, sorry...]
>Not just semi-OT, Rodrigo!
>
>Have you considered the possibility that the wierd component might be a
>FUSE?
>
>Proceed with caution.
>
>Dick
>
>----- Original Message -----
>From: Rodrigo Ventura <yoda_at_isr.ist.utl.pt>
>To: <classiccmp_at_classiccmp.org>
>Cc: Tony Duell <ard_at_p850ug1.demon.co.uk>
>Sent: Friday, September 01, 2000 6:11 PM
>Subject: Ni-MH pack topology [semi-OT, I know, sorry...]
>
>
>>
>> I was wondering whether anyone here could help me on this one:
>> I have a battery pack of a mobile phone I'd like to replace for a set
>> of AA Ni-Cad batteries (reason: cheaper!). The mobile phone even has
>> the necessary mechanical/electrical pieces necessary for the mobile to
>> work with 4 AA batteries. The question is a couple of extra small
>> terminals the pack provides. I dismantled the pack and I found out
>> that one of them was connected to the pack (-) terminal, and the other
>> one was connected to a weird component, which is connected to the (-)
>> terminal. My question is: *what* weird component is that?
>>
>> Some clues: It looks like a common 1N4148 diode: glass
>> capsule, two small copper-color cylinders, and something really small
>> in between. However, it is not a (common) diode! However, I suspected
>> it were a zenner pair (in series, symmetric polarity), and therefore I
>> tryed to measure the zenner voltage by connecting the component in
>> series with a 1K resistor, to a variable voltage power supply. In
>> fact, varying the voltage does not affect the voltage drop across the
>> component, remaining at 9.1V. At this time I was pretty sure it was a
>> zenner pair, maybe for protection or something like that.
>>
>> However, the mobile does not charge the batteries (and does
>> not recognize their presence) if this component is removed! The mobile
>> charger has about 7V (open circuit), so I was expecting the supposedly
>> zenner pair to be "open". What I did was to measure the extra pin
>> voltage: without the component it measures about 2.5V, *with* the
>> component it drops to about 1.2V. So the component cannot be a zenner
>> pair. And this was the time I had the idea to post this message...
>>
>> Thanks for any help/clues/(flames?) given!
>>
>> Cheers,
>>
>>
>> --
>>
>> *** Rodrigo Martins de Matos Ventura <yoda_at_isr.ist.utl.pt>
>> *** Web page: http://www.isr.ist.utl.pt/~yoda
>> *** Teaching Assistant and PhD Student at ISR:
>> *** Instituto de Sistemas e Robotica, Polo de Lisboa
>> *** Instituto Superior Tecnico, Lisboa, PORTUGAL
>> *** PGP fingerprint = 0119 AD13 9EEE 264A 3F10 31D3 89B3 C6C4 60C6
4585
>>
>>
>
Received on Fri Sep 01 2000 - 21:04:08 BST