Advice or help !

Hey everyone, i hope you're all good, i have a question !
if i control 2 ac loads in series with 1 relay ! ,is it normale, or there is consequences for the arduino board or the relay !
i want some clear explanation, Thanks in advance.

Hi,
What are the loads?
Voltage and current/power rating.
If they are both the same lamps then okay.
BUT if inductive or resistive loads, each with very different characteristics then you may have trouble.

Tom..... :slight_smile:

Thanks for your fast reply, please brother, explain to me why i will have trouble, what will happen !, the load will drain current from the board maybe ! why ?

TomGeorge:
BUT if inductive or resistive loads, each with very different characteristics then you may have trouble.

Hi,
What are the loads.
What voltage will you be switching.
This will make the explanation easier.

If you have two loads in series that are different, you will be getting both loads to pass the same current.
BUT the loads may not be able to conduct that amount of current and they may drop different voltages across them.
If they are inductive or one of them is inductive then the currents will not be simple constant currents but currents varying in magnitude and phase to the voltage.

Can you tell us your electronics, programming, arduino, hardware experience?

Tom... :slight_smile:

Thanks for that Tom.
The loads are 2 DC pumps 12v , 400mA, i'm using arduino nano, lcd, a relay, and a rotary encoder to navigate in the lcd, i was planning to use 2 relays, but i said maybe it's possible with one, thats why i asked.
again thanks for your time and help, appreciate it.

barhoma881:
Hey everyone, i hope you’re all good, i have a question !
if i control 2 ac loads in series with 1 relay ! ,is it normale, or there is consequences for the arduino board or the relay !
i want some clear explanation, Thanks in advance.

You said AC…
Your pumps will not be able to perform properly in series.
They are loads that will change as start and run pumping.
You will need a relay for each.
What relays are you going to use and what model Arduino?
How are you going to power your project?
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Thanks… Tom… :slight_smile:

it's on breadboard Tom, i will upload it as soon as i draw it in fritzing, i will power it with an dc adapter 12v, 2amps, the modele of my arduino is Arduino nano ,the relay caracterestiques are : 10 Amps-250 AC || 10 amps -30 dc ,the modele is :Songle
PS: for the AC, i was thinking in 2 light bulbs lol , thats why i asked the question that way .
Thanks Tom.

Ditch Fritzing. A poor hand drawn schematic is much more readable than the best Fritzing can produce, even if you don't use the breadboard view. Or get a real schematics drawing program, such as KiCAD or EagleCAD.

You should be able to run those 12V DC pumps in parallel switched by a single relay, on a 12V power source that can supply enough current for both.

Light bulbs in series: depends on the type of bulb. Incandescent will work if you use 110V bulbs on a 220V supply; LED should work if your voltage is high enough (they're typically rated something like 90-240V so two of them in series on 220V should work, but on 110V probably not); CFLs not sure if they're designed for a specific voltage (then like incandescent) or voltage range (then like LED). This all assuming the bulbs are identical in type and power rating.

Hey, Thanks for your reply and time.
i think it's not a matter of voltage !, the voltage is constant so it doesn't matter, it's a matter of amps !

Hi,
Why did you think you needed to run two 12V pumps in series when you have a 12V supply?

You can run the pumps in PARALLEL, with a single relay, and they will only load your power supply up to 800mA and will have the full 12V as their supply.

Tom.. :slight_smile:

hey Tom, i know i could wire them on parallel, i just wanted to understand things well, and as i said the light bulbs came to my mind, so i wanted to know if i was right or there is some point that i don't understand, and with your help guys i understand well now, Thanks a lot.
and Tom it's a pleasure to share with you some ideas , discussion with you is interessting !
Abraham.

barhoma881:
i will upload it as soon as i draw it in fritzing.

Please don't. Fritzing drawings are pretty, but worthless as a schematic.