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Author Topic: Overcurrent in home electronics?  (Read 258 times)
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I have a Sirius remote I picked up that I'd like to do some decoding with and customizing for projects using IR. However, I noticed that there's some overcurrent behavior taking place when I install a CR2025 battery into the remote. The LED stays lit, and any button I press and hold, causes it to turn off, and when I release, it comes back on.

I looked at the emitter via a phone camera and I see it blinking when no buttons are being pushed.

Is it possible something internally like a fuse or something is shot, or that something is causing the circuit to close?

Slight hint: I may have inadvertently tried to pair up an AC adapter or breadboard with similar power rating with the remote, which showed the same behavior, prior to use the designated watch battery. Not sure if that would've done anything, but saw this behavior on one other device...matching an AC adapter's power ratings. Do they always have to be that exact?

At any rate, any insight would be appreciated. Thanks!
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Slight hint: I may have inadvertently tried to pair up an AC adapter or breadboard with similar power rating with the remote, which showed the same behavior, prior to use the designated watch battery. Not sure if that would've done anything, but saw this behavior on one other device...matching an AC adapter's power ratings. Do they always have to be that exact?

Batteries* have a thing called ESR (Equivalent Series Resistance) which causes them to act like a battery plus a resistor. Draw a circuit with a battery, now add an extra resistor. That's ESR.

ESR means actual voltage you see from a battery will be less than the amount printed on the label. Button batteries have a very high ESR. A 3V button battery might appear to be a 2V battery if you connect a load to it.

AC adapters don't have this effect. Connecting a 3V adapter to a place where a high-ESR 3V battery normally goes could overvolt a device and kill it.

(*) Yes, all devices have ESR, but outside of batteries it's usually too small to notice.
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No, I don't answer questions sent in private messages...

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*Writes in his notebook: E...S...R.*
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