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Why wont my 2 channel relay board allow power through the output? Answered

I have a 2 channel relay board connected to an arduino nano and when i send a low signal to it i get the light on the relay board but nothing goes through the common and normally closed pin. I have the relay running on 9v instead of 5v. would this be a problem? when I test it with my multimeter it makes no difference to what is  allowed through.

please help 
Jamie

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rickharris

3 years ago

Pictures, diagrams? More information.

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Jamie Toegrickharris

Answer 3 years ago

my wiring is such a mess that any picture would be confusing. i just need to know wheather the relay should click and where to add a external battery without blowing up my arduino.

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rickharrisJamie Toeg

Answer 3 years ago

1. It is just possible that your untidy wiring is the cause of your problems! make things neat and you will be able to see errors.

2. Your 9 volt battery delivers very little current - Not enough to drive the relay. either use AA or larger cells or a wall power supply. The arduino will operate on very little current but not the relay.

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Jamie Toegrickharris

Answer 3 years ago

would you know where to put this external power source in the circuit to avoid blowing something up. I tried reconnecting the 5v and gnd wires to the new battery but the light doesn't turn on and it doesn't make any kind of humming sound. do I need a common gnd or am I going crazy.

Jamie

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rickharrisJamie Toeg

Answer 3 years ago

MUST have common ground. I would expect the relay power to go direct to the relay power in terminals. the control signal comes from the arduino.

Didn't you have any information that came with the board or look on the suppliers web site. It's hard to see from the images in the advert what is what.

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Jamie Toegrickharris

Answer 3 years ago

my nano is powered by a 9v battery with no resistor and the relay board vcc and gnd are connected to arduino 5v and gnd and this is the only power source i have on it. I havnt touched the bit with the jumper

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iceng

3 years ago

Any chance you could include a pointer to the relay board or a PDF so we can make a determination..

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Jamie Toegiceng

Answer 3 years ago

hi

the link to my relay is...

http://www.lightinthebox.com/2-channel-5v-high-level-trigger-relay-module-for-arduino-works-with-official-arduino-boards_p1141409.html?currency=GBP&litb_from=paid_adwords_shopping&utm_source=google_shopping&utm_medium=cpc&adword_mt=&adword_ct=84187195634&adword_kw=&adword_pos=1o3&adword_pl=&adword_net=g&adword_tar=&adw_src_id=1810908567_301579154_21687113474_pla-78632005276&gclid=COXJvambis0CFQaNGwodKigKUQ


feel like i should also say that it makes a humming noise and the light turns on but nothing comes through other than the com and normally open.

Jamie

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icengJamie Toeg

Answer 3 years ago

If you hit enter after pasting the URL

http://www.lightinthebox.com/2-channel-5v-high-lev...

the above streamline occurs.

Now, the relay ground and the Nano ground should be wired together although this board looks like it is completely optically isolated. I suspect that is what the jumper does for you.

Putting 9V on a 5V coil and transistor may have killed the transistor because you did not mention any hot coil smell.

The LED is on the opto-isolator input so it only indicates your nano is sending the signal to power a relay that does not have a working NPN or PNP transistor anymore.

dual relay.jpg
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icengiceng

Answer 3 years ago

Corrected wiring sorry

Click the pic to see the whole image.

nano_NPN_relay.GIF