Hello. I want to use an Arduino to control a variable resistor for testing electronic cigarettes. The resistor needs to be variable from 0.05-3.0 ohms. The attached graph shows the power received at variable resistances. The electronic cigarettes outputs from .5-9 volts and up to 55 amps. I would like to have some room to test more powerful devices if possible. Does such a device exist? If not, how would I create one? Thanks.
The current is such that there is no commercially available variable electronically controlled variable resistor (digitally controlled potentiometers are commonly called "digipots") capable of doing that. Digipots exist, but are typically 10k ohm resistance or higher, with current limits in the range of a few mA. They're for reference voltages, not high power operations.
Your best hope is a number of low Rds(on) MOSFET's switching power resistors, all set up in parallel. With a logical progression of batteries (ie, powers of two) you can generate a range of resistances by choosing which MOSFETs to turn on.
You need something like this on steroids:
Google "electronic dummy load"
That's an interesting device. I agree that the OP needs a large mosfet or multiple mosfets in parallel and
then maybe he can PWM them with the arduino.
You could try a number of these in parallel on heatsinks (or the same heatsink) and PWM them.
I am curious as to how you are testing the electronic cigarettes. How are they able to output 55A?
Weedpharma
weedpharma:
I am curious as to how you are testing the electronic cigarettes. How are they able to output 55A?
About time someone called "XY Problem"!
Definitely sounds like an xy-problem.