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How would i disconnect and reconnect 12vin every 2 hours to my circuit board?

I was thinking about using a 555 timer to reset the power but i'm not sure how to do it using a 555 time

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closed as too broad by Voltage Spike, DoxyLover, Lior Bilia, abdullah kahraman, Dmitry Grigoryev May 3 '18 at 6:39

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ You could use a small microcontroller to count up the time, or you could use an oscillator to drive a binary counter and tap off whatever corresponds to 2 hours from it and use that as a signal to disconnect your power, using a relay or a FET. \$\endgroup\$ – hatsunearu Apr 25 '18 at 11:13
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    \$\begingroup\$ @hatsunearu Please don't answer questions in the comments. There are numerous problems with that, which is why the comment field has a warning about it. \$\endgroup\$ – pipe Apr 25 '18 at 11:20
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    \$\begingroup\$ I see what seems to be an X-Y problem here. Particularly if said 12V supply is also meant to be the power source for the 555 and relay. Maybe you should describe the real reason you think you need to cycle the 12V power - it is just possible there may be a better way to achieve your real goal. \$\endgroup\$ – Michael Karas Apr 25 '18 at 11:25
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    \$\begingroup\$ What sort of current? I can think of devices drawing 10s of uA to 10s of A at 12V nominal, and the answers aren't necessarily the same. Also what source (car battery, mains,...)? \$\endgroup\$ – Chris H Apr 25 '18 at 12:49
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    \$\begingroup\$ Possible duplicate of Reset Power using 555 timer \$\endgroup\$ – dlatikay Apr 25 '18 at 17:47
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How would i disconnect and reconnect 12vin every 2 hours to my circuit board?

Just go unplug the power every 2 hours, then re-connect it.

If you want it done automatically, the simplest is probably one of those timers you can find in home improvement stores. They should be able to be set up to run something for 1½ hours every 2 hours, for example.

If you want your own circuit to control the power, the simplest at your apparent level of electronics knowledge is to use a relay. That's basically a electrically-controlled mechanical switch. These things are quite forgiving, robust, and the control is isolated from the switch part. There are lots of answers here already about how to control relays from digital signals.

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    \$\begingroup\$ Well if you have that much money to hire Olin you should hire a consultant to design it for you. \$\endgroup\$ – Andy aka Apr 25 '18 at 11:48
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    \$\begingroup\$ @Ricky well, personally I would have thanked Olin for giving three possible solutions rather than just ignoring your question because it lacks a lot of information. I personally find Olin's answer (given in less than 20 minutes) very helpful: if it is something you have to do for a day, it is faster to just do it manually. If you need limited precision, a cooking timer is fine. If you need it electronically controlled, the main suggestion is to have a relay, like he suggested. And for the controlling, there are a lot of ways. \$\endgroup\$ – frarugi87 Apr 25 '18 at 13:08
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This question seems ripe for leading to an XY problem. Can you tell us more about your issue: why do you feel you need to kill the power every 2 hours?

At any rate, if you really do just want to kill power periodically, you could use a programmable time clock/time switch. These are readily available from electrical wholesalers. The ones i've worked with are basically a relay (or two) that open and close at certain times that you program them to (when I say program, it's not coding/firmware, there's many with a relatively easy to use keypad interface on them).

You might get more helpful information if you can give more details about your issue, however.

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