I want to use the arduino to control ONLY the polarity of the peltier module. I will be using the power supply machine (portable kind) to control the magnitude of current supplied to my peltier module, not using the arduino. this said, I won't be using a dpdt relay as this is more of a mechanical switch to manually control the polarity of the peltier module.
do i thus need a H-bridge? If so, what kind of H-bridge? given the simplicity of arduino in just changing polarity, what are the electrical components I need? thank you!
You can use a dpdt relay to control tha polarity of an H-Bridge but what advantage do yiu expect to gain from an H- bridge over a relay ? Wht do yiu need an arduino ?
however, what if i want to use arduino to control the current and voltage as well as polarity? can i hence chuck away the dpdt switch? can an arduino be used alongside a power source machine? using H-bridge is not good am i right considering that there is considerable voltage drop across H-bridge which is undesirable. any good weblinks for my issue? thanks! i am utterly loss at the circuit configuration for peltier and arduino
ok i need about 3A of current and 12V for my peltier. how should i go about building my circuit? what materials do i need? what model or type of h-bridge is recommended for my peltier of rating 15.4V and 7A with temp differential 69 deg C? i need to control current, not voltage for the case of the peltier module.
just to check the things i need for my objective which is to be able to adjust the current either through the power supply machine or through arduino (god knows which is better) and in a way to ensure that temperature of peltier do not exceed a limit (need for temp controller). Also with a H-bridge (guess it's the only possible way to reverse polarity of peltier without using dpdt switch) linked to the arduino
so i will need H-bridge (which model do u recommend? L298N?), arduino uno, peltier, power supply, temperature controller (any recommendations folks>?)
do i need capacitors? inductors? i am quite lost as to the additional required components and why. hope someone can elucidate thanks!
The garagelab circuit with the MOSFET is not capable of polarity reversal.
Most Peltier modules are designed for 12-15 V and about 7 amperes of current. Your power supply must be capable of supplying more than that. If you insist on polarity reversal, you will need a high power H-bridge to handle 7 amperes of current -- the L298 certainly won't. I suggest a brushed DC motor driver from Pololu, like this one Pololu Simple Motor Controller 18v7 Nothing other than the Arduino is required to control the H-bridge.
@BillHo thanks for showing me that circuit but i guess it looks abit unfathomable considering im a beginner in circuit design
You're not designing it. It is already designed. It is a recipe. Just cook it. That's what cookbooks are for. Don't ask questions. Just do it. I've built hundreds of circuits that I couldn't have designed but funny thing, after I built them and saw them work, I started to "get it" and eventually modified some of them after understanding how they worked. You don't always have to understand something you're building if you are capable of reading a schematic and connecting wires correctly. That circuit is exactly what you need. Suck it up and build it.
Also: you won't get the maximum temperature differential, that is the max it can do with zero heat flow. Any heat flow at all will reduce that. So the cold side must be well-insulated and if you want the cold side to get colder, you must make sure the hot side has a lot of heat flow away from it. So a nice big heat sink and a lot of airflow to get it as close to ambient as possible.
@jremington
"Most Peltier modules are designed for 12-15 V and about 7 amperes of current. Your power supply must be capable of supplying more than that. If you insist on polarity reversal, you will need a high power H-bridge to handle 7 amperes of current"
oh to think i have been using only 2-3A of current as I was afraid that 7A might burn out the peltier module isn't it. and plus u shd only use 50-80% of the max V and A rating of the peltier for it to work in a decently efficient manner am i right to say?
the power supply machines in my lab provide at most up to 4A even if I preset it to 7A. I guess 4A is alr high haha considering that I am using one of the hot sides of the peltier to melt chocolate in an aluminium muffin cup, meaning to say that the muffin cup is my heat sink (the other side of the peltier has a proper heat sink though when that side becomes hot). I do hope the muffin cup together with a 4cm by 4cm copper sheet will be sufficient as a heat sink for the side of the peltier in contact with the Aluminium muffin cup.
this is the pic of what i am doing now. i was afraid 7A would burn out the peltier for the hotside of the peltier melting the chocolate (of course I am cooling and hardening the choc back tho with reverse polarity)
bearing this in mind do i still need the polulu motor controller given tht i might just be handling 3-4A of current for my peltier not to be spoilt?
or h-bridge suffice? do check the picture attachment thx!
