Whats wrong?

Discussion in 'The Projects Forum' started by Wind23, Apr 28, 2013.

  1. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    I am working on this circuit and i am having problem with the relay whereby it does not switch nicely and seems to make weird noise as if it got stucked.

    Here is the circuit. http://www.zen22142.zen.co.uk/ronj/rt5.html

    Can anyone help me please? The relay is a 12vdc relay and i gave 13V as power supply.
     
  2. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    The 13V is sourced from a car battery and another weird thing i found out recently is the weird noise sometimes happens when i am testing it with a low current 12v solar panel but does not happen when connected to car battery. Why does this happens? Does it mean it only operates at low current and not at high current? Pls help.
     
  3. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    That means it only operates well when plenty of current is available.
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,052
    3,244
    If the voltage from the solar panel to the relay coil is actually less than 12V, then that may cause the relay to chatter. What current is going through the relay contacts?
     
  5. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    Hi, if connected to the car battery @ around 13v, the relay gets around 13V and the relay does not make clicking sounds whereas if connected to the solar panel(Voltage change as sunlight increases n decreases), the clicking sound of relay is heard.

    I think it has nothing to do with supply voltage as a 12v relay can work with 13V or lower but the current from the car battery might be higher so causing the problem. Please correct me if i am wrong.

    Thanks.
     
  6. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    Is it with low current then the relay works normally?
     
  7. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    You have it exactly backwards. A car battery is a very strong source of current. Having plenty of current makes it work right. Clicking is not working "right".
     
  8. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    Ok. Another weird thing i see is the relay clicking sound appeared immediately when i connect it to the small solar panel with the thermistor heated under the sun but when i connect it to car battery with the thermistor under the sun, no clicking sound but relay does not switch and i assume its because its not hot enough. The circuit only works under very hot conditions i supposed.
     
  9. WBahn

    Moderator

    Mar 31, 2012
    17,777
    4,804
    Put a potentiometer in place of the thermistor so that you can test the circuit and play around with it.
     
  10. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    Hi there is a pot in the circuit given n i m following that. I m wondering if i need to change the pot and series resistor values as the system reacts very slow. As mentioned earlier when connected to car battery there were no clicking sounds n i assume its working well but it took a long time to turn on the load that i wish to run after the relay shifts .
     
  11. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    For the time control i m not using the 2 pots tat were connected with the 100k resistors. Just connect 100k resistors with the diodes.
     
  12. Wind23

    Thread Starter New Member

    Sep 26, 2012
    22
    1
    Can anyone tell me how to solve this problem please ? How do i do on-circuit testing of the components soldered on pcb?
     
  13. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,015
    1,531
    How can you expect to make random changes in a circuit and have it work?
    Things that are in the circuit schematic are there for a reason.
     
Loading...