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  1. #1
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    looking for a pulse relay

    I have a thermostat project which run from 2AA batteries
    The microprocessor has a minimum consumption current
    In fact the whole project run in just 1-2 miliamps.
    The big issue is the output of thermostat.
    Most thermostats, to conserve power , and change the battery maybe once a year , use latching relays.
    2 coils take too pins from micro
    1 coil is complicated to drive
    I heard about pulse relays. One pulse = ON; take the power out and still ON, like a latching relay. Next pulse, on the same line, turn it OFF.
    I found circuits to drive 1 coil latching relays, but most of them use capacitors, which of course will drain my battery
    I need a suggestion of a manufacturer for this PULSE relays.
    Contacts 2 A, coil 5-12 VDC

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  2. #2
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    Re: looking for a pulse relay

    If you are switching about 1A AC you can use a current transformer that will give you 50mA to hold on a normal relay and to charge your battery.



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  3. #3
    Member level 3
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    Re: looking for a pulse relay

    Thanks Vbase, but maybe i did not express myself correctly
    I need to have the power on the PIC pin just on the transition moment, then the pin will drop at 0 volts and no consumption.
    The relay, must maintain the last position.
    At next pulse, it must toggle the opposite way. I do not know what will be the voltage on the contacts of the relay. Every HVAC manufacturer has its own way of internal activating the heat or cool.



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