Arduino Forum

Topics => Product Design => Topic started by: patrickmueller on Aug 21, 2013, 01:16 pm

Title: Control ac current
Post by: patrickmueller on Aug 21, 2013, 01:16 pm
Hello Forum

I'd like to control a ac current with my arduiono uno board.
Let's say I've a ac source 9v <1mA. With a digital pot I'd like to control the voltage of the source.
Over SPI I can send a value between 0-128 to the digi pot. 0 should result an output of 0v, 128 of 9v.

I could control a dc source with a transistor an the digi pot but how can I do this with a a source?

Thanks for any suggestions!

Patrick
Title: Re: Control ac current
Post by: groundFungus on Aug 21, 2013, 04:20 pm
There are digital pots that will handle an AC signal.  If the signal is truly AC (both above and below ground) you must supply it with a bipolar supply.
Title: Re: Control ac current
Post by: patrickmueller on Aug 21, 2013, 05:23 pm
Thanks for the answer!
So if it is not a "true ac signal" I don't need a ac-digi-pot?

Patrick
Title: Re: Control ac current
Post by: groundFungus on Aug 21, 2013, 05:54 pm
If the signal NEVER goes below ground then it is more like pulsating DC and a "regular" pot should work.