I want to know how to make a heater, i thinks it would be a good idea to take one big piece of conductor and pass voltage throught it.
But i also thought that i can take a lot of simple resistors.
I serached for a create heater and i check this one but i dont know if it is trustworthy. (link below)
But i also thought that i can take a lot of simple resistors.
Yes you can, you can use any resistor or collection of resistors in series or parallel. The only problem is the current it will take. Each resistor has a power rating, that is the maximum power it can dissipate, that is the maximum power it can supply in heat.
This power is derived from the current through the resistor multiplied by the voltage across it. If you fiddle about with ohms law you get the formula
Power = V2/R
You need to work out how much power you need to supply to heat your box. An incubator normally uses an incandescent light of about 40W and providing you live in a sane country you can buy these easily.
Resistors can be purchased in any power rating from 0.125W to hundreds of watts. When I need a small heater of (imagine) 10W, I'll buy 2W resistors and put 5 of them on a circuit board. If I'm heating air, a little fan of whatever style suits my installation blows air over the resistors. If I'm heating an object, I'll get the resistors touching the object. The resistor value depends on the voltage. For 12V, I'll use 120 Ohm resistors.
You can get self-adhesive pads to heat objects. From just a few watts to hundreds. They can get expensive, $70 or so even for small ones. You can also buy resistance wire heaters to wrap around objects or pipes.
While it's possible to buy Nichrome wire and make your own heater, it's very difficult - you need a lot of wire and you need to wind it in a way that maximises heat transfer and doesn't let the wires touch each other. Those heaters you found look pretty neat. I would buy one of them.
Another example. Every year we make several hundred heater boards to keep laser diodes warm(snow plows). Each heavy FR4 board has four 5 watt wire wound resistors mounted tightly to the circuit board that has a hole in the middle for the diode.
You didn't state how many Watts you want to dissipate, but in principle, you can maybe use what works fairly well to heat Nasmyth telescope mirrors (outdoor/winter use) or similar gear.
One thing, commercial heaters are not even supposed to be left in a room alone on. It makes sense to buy one of these because of their safety, but even they are somewhat dangerous. They are required to have certain safety features though. Some of these are tilt switches and materials rated to the heat the heater will create.
Paying an extra 20 bucks to not start a fire or give yourself a shock is worth it. On another note, creating the heater would be a fun experiment. It would be interesting to try, but I would NOT use this heater for any
amount of time.
Wait, I just read the last line about it being in an incubator.
You would only need a very small heater for that. A diy arduino controlled heater would be perfect. A cement resistor like:
This with an attached heatsink would work perfect.
An commercial option would be:
Then you can have an accurate temperature control.
