+ Post New Thread
Results 1 to 6 of 6
  1. #1
    Advanced Member level 4
    Points: 8,778, Level: 22

    Join Date
    May 2002
    Posts
    1,184
    Helped
    27 / 27
    Points
    8,778
    Level
    22

    relay lamp avr

    Hi
    My avr micro 8515 on/off a relay by a ULN2803 driver,when relay have no load everything goed well,but when I attached a 100w lamp as load to relay contacts the avr resets when turns the lamp OFF.

    I used the snubber circuit across contacts but problem remains.

    Please guide me.

    Regards

    •   AltAdvertisement

        
       

  2. #2
    Advanced Member level 5
    Points: 36,491, Level: 46
    flatulent's Avatar
    Join Date
    Jul 2002
    Location
    Middle Earth
    Posts
    4,629
    Helped
    494 / 494
    Points
    36,491
    Level
    46

    avr at90

    you might want to try a triac/scr type switch. Some of these come with opto isolator type inputs. They turn off by waiting until the ac line current reaches zero and then opening up. This way there are no severe line transients.



    •   AltAdvertisement

        
       

  3. #3
    Full Member level 5
    Points: 4,910, Level: 16

    Join Date
    Jan 2003
    Location
    Ireland
    Posts
    268
    Helped
    19 / 19
    Points
    4,910
    Level
    16

    realay noise on avr

    How is your snubber ?

    Single 100nF or 220nF usualy solves this problem.



    •   AltAdvertisement

        
       

  4. #4
    Advanced Member level 4
    Points: 8,778, Level: 22

    Join Date
    May 2002
    Posts
    1,184
    Helped
    27 / 27
    Points
    8,778
    Level
    22

    avr + relay driver

    I replaced the at90s8515 which is not good and very noisy with at90mega16 and the problem was solved but I made an adaptor to fit it.

    regards



  5. #5
    Full Member level 4
    Points: 4,651, Level: 16

    Join Date
    Nov 2001
    Posts
    236
    Helped
    9 / 9
    Points
    4,651
    Level
    16

    opto isolator relay noise

    Hi,

    I don't really know AVR micros, but I share some of my experience with PIC.

    I have a circuit with PIC16f876 that turns 30A (220 AC) relay; and even producing noise with a connection made with touching to wires of the load, every thing works well.

    I use 100nF Cap from Vss to Vdd

    HH

    NeuralC



    •   AltAdvertisement

        
       

  6. #6
    Newbie level 6
    Points: 1,648, Level: 9

    Join Date
    Jan 2004
    Posts
    13
    Helped
    0 / 0
    Points
    1,648
    Level
    9

    relay spark

    Did you add "Freewheeling" diode across the relay coil?

    If your relay and your MCU are operated at different supply (such as relay at 12V, MCU at 5V), suggest to add some opto-isolator at the relay driver input.



--[[ ]]--