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Miniature Glass Component With Resistance Not A Diode In A Rechargeable NIMH Battery Pack

I can't recall what a glass-enclosed device is called which I think is a capacitive component with resistance. This component shows 11k ohm resistance and no difference in polarity, and checks equally the same with a DMM diode test.

This just looks like a small axial lead glass diode (~3.8mm long) without a cathode mark, copper colored dies at each end with a tiny gap between them.

The pack has three external terminals, of course (+) and (-) and a 3rd sense/charge terminal.

The component's place inside the battery pack is between a third external terminal and joined at a junction with the external negative terminal. The battery negative battery contact is connected straight to the external (-) terminal, and this device is between the negative terminal and the 3rd external contact. (not too swift at ascii art).

Thanks

--
Cheers, 
WB 
.............
Reply to
Wild_Bill
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It's a thermocouple to tell the charge controller how warm the battery pack is getting while being charges. A sudden peak in temperature tells the controller the pack is fully charged. At that point it may either shut off or go to a trickle mode, depending on the charger design.

Paul

Reply to
Paul Drahn

Not a thermocouple, but a thermistor. A thermocouple would have a couple Ohms resistance, tops. 11K sounds very right for an average thermistor. otherwise, what you say about temperature measurement is right.

Jon

Reply to
Jon Elson

Yup. Right you are.

Paul

Reply to
Paul Drahn

Thanks, Paul.. I wasn't thinking of temperature sensing but I believe you're correct. The CT types shown in the Semitec pdf appear to be the same.

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I attempt to be thorough about details when asking questions, but left out some this time.. the glass component was glued to the plastic jacket of one of the cells. Also, there are 2 Klixon temperature protectors inside the pack case.

I've often seen bimetal type temp protect devices used in rechargeable packs, and fewer self-resetting polyfuse devices, also resistors a couple of times and diodes a couple of times.

-- Cheers, WB .............

Reply to
Wild_Bill

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