AskElectronics

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This is a technical ELECTRONIC ENGINEERING community, covering practical, component-level circuit design and repair, electronic circuit theory, electronic components, tools and equipment.

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cr2032 batteries have negative voltage - how is that possible? (lemmy.dbzer0.com)
submitted 3 weeks ago* (last edited 3 weeks ago) by diyrebel@lemmy.dbzer0.com to c/askelectronics@lemmy.ml
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I volt-metered a cr2032 battery and the result was like -1v. No, I am not getting the polarity of the probes mixed up. My other batteries are fine. I also measured using a better true RMS DMM, and same result. Does this result make sense?

(edit) Another question: what if I insert into an appliance upside down, to reverse the polarity. Will I have a +1v battery?

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Replacement Bulb for Ultrafire WF-500 Flashlight (cdn.tcb13.com)
submitted 2 years ago* (last edited 2 years ago) by TCB13@lemmy.world to c/askelectronics@lemmy.ml
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Some years ago, before LEDs were a thing, I bought an Ultrafire WF-500 Flashlight that features a Xeon light bulb. As you might imagine the bulb reached its lifetime and burned away.

Now a replacement bulb is available here https://www.ebay.com/itm/321916301663 the thing is that it will cost me 35€ and for that price I could just buy a new LED flashlight.

Now I was considering trying to adapt a generic LED bulb like this one here https://www.aliexpress.com/item/1005002419159094.html?mp=1.

Anyone else with this model of flashlight succeed at a similar mod? Any LED bulb recommendations? Or... is there any other source for the original bulb at a lower cost?

Some photos:

Thank you.