USB powered HP41

[Neve]

(09-07-2017 11:55 PM)Jlouis Wrote:  Hi,

For now, I just want to answer your #1 question:

Although I don't know the nominal eletrical current necessary to supply the HP 41 and the card reader, I don't think that a source of only 0.15A would be enough to do the task alone.

The problem here isn't a question of increase Voltage. The source must have the necessary power to do the job, i.e., nominal voltage multiplied by the current in Amperes.

The current is actually a function of the voltage divided by the resistance (load).

If you know the demand current for using the card reader, you will be able to design your source.

Now, HOW you are suposed to CONNECT the power source to the main board of the calculator, is another issue.

Good luck,

Cheers

JL

Problem solved, it is 1A, not 0.15A, as Sylvain Cote pointed out.
Error corrected in my original post.

Thank you.