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coin cell battery Answered

Question about flashing red LED:
I have a simple circuit--switch, battery, resistor, LED. Today, when I clicked the switch on, the LED came to life very slowly, as of it were fading in. I have never seen this behavior before. Is it the battery? (3V, 2032 coin cell and 100ohm resistor).

Thanks.

Discussions

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Orngrimm
Orngrimm

7 years ago

Also as a sidenote:
I noted on some cheap (2$ for 10 pcs) keyring-LED-lights that if it gets really cold (like -10°C) the batteries tend to die and sometimes they fade in... Thats a simple matter (in my case) of the slowed down chemical reaction in the battery which comes into swing very slowly (and maybe even heats up the Battery inside a little bit).

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KJ4ZVQ
KJ4ZVQ

7 years ago

Honestly, you shouldn't need the resistor. Yes, your battery could be draining, but more than likely the resistor is the problem in this circuit. Someone else from the site may correct me, but to my knowledge, most led's are 3 volt, so the resistor would do nothing but slightly under power the circuit. Best of luck!

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steveastrouk
steveastrouk

Reply 7 years ago

Depends on the colour. That said, flashing LEDs usually have their own current control, so you don't need to add an external resistor at all !

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yongeeks
yongeeks

Reply 7 years ago

Thank you. Yes, the resistor might be the problem. This is first flashing LED I've used, so I treated it as I would a steady LED.