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  1. #1
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    design a timer which turn a relay ON every 3 hours whitout a microcontroller

    hi. I have an incubator which is consisting of a heating source, a themostat and a DC motor for rotating eggs. the DC motor should be turned ON every 3 hours. I do'nt want to use a microcontroller.
    do you have a circuit?
    is the relay necessary for switching the motor? I mean can the timer directly switch the motor?
    thanks
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    Re: design a timer which turn a relay ON every 3 hours whitout a microcontroller

    You want a cycle timer. Do an internet search



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  3. #3
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    Re: design a timer which turn a relay ON every 3 hours whitout a microcontroller

    Hi,

    There are small SPCs.

    ***
    And you need a complete flow chart.
    You can't switch ON a device without switching it OFF. If you want to switch it OFF, then you need to define at least the timing.

    is the relay necessary for switching the motor? I mean can the timer directly switch the motor?
    How can we know? We don't know anything about your motor, and we don't know anything about the "controller".

    Usually there are specifications like voltage, current and type of motor (DC, AC, 3 phase, BLDC, stepper....)

    Klaus
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  4. #4
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    Re: design a timer which turn a relay ON every 3 hours whitout a microcontroller

    Hi,

    A ripple counter IC like the (CD)4060 if you don't need an extremely precise 3:00:00h, it would need a transistor to drive either the relay or the motor directly. ICs like the LM193 can drive motors directly, but only little two-wire "toy" motors that operate at low current.



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