I need about 1.5 to 2 Amps of constant current to heat up a nichrome resistance wire. I know the Arduino only puts out a max of 500 mA, but is there a way to amplify this up to what I need using a transistor? I would also need to be able to be able to be turned on/off as I don't need it to constantly supply the current. Something simple would be best.
Thanks for any suggestions!
Whats the resistance of the resistance wire? 
Google using a transistor as a switch , or if it’s AC , solid state relay .
Simplest, although not cheapest, is to use a motor driver with current feedback. The Sparkfun Monster Moto is a good example although you do need to add a capacitor on the feedback pin for correct averaging of the Arduino PWM frequency.
I smell an x-y problem
Why would you need constant current into a piece of nichrome wire and never mention the voltage? You’re not providing details, only asking about your solution which probably isn’t a solution at all.
What are you actually trying to accomplish with this heater?
I am using the Arduino, so I am using the 5V out.
It is a solution as shown in various published literature. I have also tested it with a power supply that lets me choose any constant voltage or constant current and it works. Therefore I know I need 1.5-2.0 Amps of CC. I need to know how, or if it is even possible, to do this using only an arduino and whatever other small circuit components I may need.
When nichrome wire has that amount of current pushed through it, it heats up incredibly hot. So when I have a loop of this nichrome wire tensioned against a cable, it will cut through the cable.
WattsThat:
I smell an x-y problemWhy would you need constant current into a piece of nichrome wire and never mention the voltage? You’re not providing details, only asking about your solution which probably isn’t a solution at all.
What are you actually trying to accomplish with this heater?
You should google bag sealer or impulse sealer circuits . They work the same as what your trying to do.
They work of a 240v to 9v transformer rated at amps needed. Would need an ssr to control wire temp on 240 side
What is the voltage output of your power supply when it is providing desired current into the nichrome wire?
You must know this voltage before you can do anything further with this project.
danielllarry13:
I am using the Arduino, so I am using the 5V out.
It is a solution as shown in various published literature. I have also tested it with a power supply that lets me choose any constant voltage or constant current and it works. Therefore I know I need 1.5-2.0 Amps of CC.
Are you saying constant voltage did not work? That would greatly surprise me.