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What happens if you put a simple circuit like a timer with a 555 IC and, let's say, a DC motor, including 3 AAA batteries in a freezer (around -15 centigrade) in a working state?

If it does harm the IC or DC motor or batteries, is it just because of the freezing temperature or the moisture - or both?

Is there any way to avoid damaging the equipment, like a vacuum or foam (as insulation) or a little heater?

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  • \$\begingroup\$ more than related: ham.stackexchange.com/questions/12014/… (practically the same question, just on a different site) \$\endgroup\$ – Marcus Müller Jan 6 at 13:14
  • \$\begingroup\$ Not as extreme as my old question, but slightly related. \$\endgroup\$ – Harry Svensson Jan 6 at 14:11
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    \$\begingroup\$ Most electronics are self-heating to some extent while working. -15C is not usually a problem unless condensation forms, except for batteries. \$\endgroup\$ – pjc50 Jan 6 at 17:38
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    \$\begingroup\$ The door seal on a freezer will usually accommodate two thin wires, so perhaps you could have everything except the motor outside. \$\endgroup\$ – Andrew Morton Jan 6 at 19:42
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It really depends on the parts you have, especially with the IC and the motor.

ICs are always temperature rated and you can see their working range in the datasheet. If an ICs gets to cold it can get fractures in the small inner structers, which can be as small as several nanometers and are quite fragile due to that. But a 555 will have no problems with -15°. The moisture is not really problem, except when you activly cool the chip below the temperature of the environment.

The motor itself will also have no problems with the temperatur, but you have to choose one which is (again) rated for that temperature range. The reason is that the lubricant of the bearing has to keep its greasing properties.

The batteries are the biggest problem. At -15°C they will have a strongly reduced chemical reaction speed, which increases the internal resistance a lot. You really want to keep them warm during operation.

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  • \$\begingroup\$ does the external electricity it self can harm the freezer or interrupt its working in anyway? \$\endgroup\$ – newbie Jan 6 at 16:16
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    \$\begingroup\$ For that you would have to have big switching currents. And by big, I mean big. Or in other words: Way more than a AAA-battery can deliver ;) \$\endgroup\$ – jusaca Jan 6 at 18:05
  • \$\begingroup\$ thanks, what do you think about insulation with foam, can that help? \$\endgroup\$ – newbie Jan 6 at 18:12

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