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  1. Replies
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    Closed: Re: damaged remote control

    I treid this but not working.
  2. Replies
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    163

    Closed: damaged remote control

    hi dear experts.
    last night the following remote control fell in the tea pot and now it is not working.
    what is the problem?

    155008155009
  3. Closed: Re: How to modify hysteresis of cross coupled comparator

    the hysteresis is a voltage-band defined in op-amp comparators which determines the output level based on the non-inverting input. if you won't to use hysteresis, the output will go to chattering and...
  4. Closed: Re: What is the difference between IRF510 and IRF510N?

    both are N-Channel 5.6A 100V.
  5. Closed: Re: how to design a thermostat without Microcontroller?

    LOL
    the discussions are focused on hystersis for 10 days and now you find it out?:laugh:

    the probelm has been fixed and the feedback network provides about 1C HYSTERSIS. (330K/1K). the thermostat...
  6. Closed: Re: how to design a thermostat without Microcontroller?

    How to do span control?
  7. Closed: Re: how to design a thermostat without Microcontroller?

    Mission Complete!

    Fistly, I should express my fullest appreciation to @betwixt, @Klaus, @kripacharya,@c_mitra, @barry, @FvM, and @andre_teprom and those who valuable guidlines and patience helped...
  8. Closed: Re: how to design a thermostat without Microcontroller?

    excuse me, I did'nt realize where 4.7k resistor should be connected. your Grammar is too native and hard to me to understand. LOL
  9. Closed: Re: how to design a thermostat without Microcontroller?

    c1 is connected to op-amp power rails.
    today I will connect 0.33uf and 0.1uf to input andoutput pins of 7805 Regulator as decoupling Caps. please say their type & capacity too.

    - - - Updated - -...
  10. Closed: Re: how to design a thermostat without Microcontroller?

    BY Proteus.
    here is the new design.
    154468154469
    154470
  11. Closed: Re: how to design a thermostat without Microcontroller?

    Your words about creating hysteresis are opposite of the experts´ comments in this thread. moreover, Nothing is trial and error approach, Nothing. My room is full of papers which have filled with...
  12. Closed: Re: how to design a thermostat without Microcontroller?

    Today, 330k/1k resistors tested but the chattering still persists. Simulation shows 10mv hysteresis with no chattering but in practice not . It makes me nervous.
  13. Closed: Re: how to design a thermostat without Microcontroller?

    Yeah, you are right Mr. Andre.
    I´m tied up and tomorrow will share the conclusion. Thanks for your patience, that is very nice of you.
    After getting results, the unnecessary parts of the thread...
  14. Closed: Re: how to design a thermostat without Microcontroller?

    the calculation of hysteresis resistors is based on the link below: (with Vhysteresis=0.005v then R1=1K&R2=2.2M)
    https://www.electronics-tutorials.ws/opamp/op-amp-comparator.html
  15. Closed: Re: how to design a thermostat without Microcontroller?

    unfortunately not. The feedback network calculated to have 0.5C Hysteresis. When the temperature reaches to the desired point (37.7), the relay goes to chattering and makes a sound like JIZZZZZZ and...
  16. Closed: Re: how to design a thermostat without Microcontroller?

    the relay is fed from input pin of 7805 regulator, exactly after diode bridge. also a 10uf capacitor is connected to the output pin of 7805 Reg.
    a 0.1uf cap. paralleled to the relay coil.
    the...
  17. Closed: Re: how to design a thermostat without Microcontroller?

    Thanks, what are the capacity of the capacitors?
    Where must be connected?
    How can I control the hystersis?
    (Also The relay manufacturer is Tianbo which is 5Vdc. )
  18. Closed: Re: how to design a thermostat without Microcontroller?

    I modified the schematic. the feedback resistor is 2.2M. the power supply is 5v and the relay is 5v too.
    I have a suggestion: in your opinion, if I change the relay to a 3V relay with that same...
  19. Closed: Re: how to design a thermostat without Microcontroller?

    Firstly I appreciate Mr. @andre_teprom to reopening the thread.
    dear friends, after some studies I made 0.5C hystersis-enabled thermostat. before going forward, I give you an expression about the...
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    Closed: Re: a substitute for a 5V relay

    What number?
  21. Replies
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    395

    Closed: a substitute for a 5V relay

    Hi dears.
    I have a comparator circuit which switches a 5V relay ON or OFF. when the output of comparator saturates toward the positive supply rail,+5V, the relay will go ON; inversly, when the...
  22. Closed: Re: how to design a thermostat without Microcontroller?

    your indescribable concerns & kindnesses will not be forgotten.

    but another question still remains. what is the use of this free OP-AMP? How it should be connected?
  23. Closed: Re: how to design a thermostat without Microcontroller?

    Special thanks to you for valuable concerns. but I have still some questions.

    for power supply, I used full-wave rectifier with 470uf capacitor which a 7805 Regulator fixes the output voltage to...
  24. Closed: Re: how to design a thermostat without Microcontroller?

    thanks for your attention.
    I answer your questions one after another. I mark my answers by *.

    As you have given an exact value for the set temp (37.7C) can I assume that it can be 37.7+/- 0.1C?...
  25. Closed: Re: how to design a thermostat without Microcontroller?

    yes you're right. but after doing some researches & simulations I find that the best hysteresis is 0.5°C. excuse me brother.

    now with 0.5°C, what are the value of feedback resistors?

    - - -...
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