Controlling current from arduino (12v)

Using Arduino Motors, Mechanics, Power and CNC
1

Hi, I am new to arduino, I only make a parking sensor for my car with it.
Now I want to do something different.
I need to provide three different currents, in 12v
-2a
-0.25a
-0a

It is to power lights, I just want to control from the arduino, to give the necesary current that I need. How can I make this? with a relay? thanks in advance, I am really a noob in this.

2

What is 0a? Look in playground, in output section.

3

I assume 0a means off.
Also I assume that -2a
Does not mean -2A but just 2A.
Basically you can't control current from an arduino, but I don't think you need to.
One way of dimming a light is to use PWM. You need to connect a logic level FET to the arduino pin to do this.

4

I am working with an electronic dead bolt
With 2a at 12v it will close, with 0.25a at 12v it will keep it closed. And with no current, the lock will open. I just need to control that from the arduino.
I think I need to use a relay for that? can you recommend me anyone that will work?
Thanks

5

http://ruggedcircuits.com/html/circuit__7.html
http://ruggedcircuits.com/html/circuit_gallery.html#TOC
For relay
Arduino Playground - HomePage Almost any automoto (12V) relay can handle 2 A.

6

With 2a at 12v it will close, with 0.25a at 12v

Sorry but that makes no sense in electronics. If a coil will take 2A given 12V there is no way that it can take 0.25A at 12V. To get it to take a lower current you have to change the voltage. You can not do that with a relay.
You might be able to do it with a PWM output feeding a FET, so that in the low current mode you are in effect switching the coil on for a small percent of the time and off for the rest. The average current will then drop but the peak current will always be the same.