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Topic: 12V Demux (Read 1 time) previous topic - next topic

Enter_Kratos

Jul 16, 2012, 11:36 am Last Edit: Jul 16, 2012, 11:40 am by Enter_Kratos Reason: 1
Hey guys,

I'm fairly new to this sort of thing; only really played around with some servos, LEDs and Pots.
What I'm looking for is either a digital pot that can output voltages between 0 and 12volts which through my searching doesn't appear to be available or
a demux which can output up to 12volts so as to fit resistors of various strengths on the different outputs to the same effect.

Does anyone who has more of a grounding in this sort of thing have any suggestions?

EDIT:
Just found this:
http://uk.farnell.com/analog-devices/ad5293bruz-20/ic-dig-pot-1024pos-20k-14tssop/dp/1827274

Would this be able to be used for this purpose?

Cheers,

Kratos

Magician

Depends on how accurate voltage you need, better to use DAC (digital analog converter) than scale output with OPA. 8 or 12 bits available, interfacing circuitry with drawings usually printed in data-sheets.
Or you can even create one using resistors in R-2R ladder configuration.

Grumpy_Mike

Quote
Would this be able to be used for this purpose?

Yes but you have to have a 12V power supply to drive it and also give it a logic supply of 5V.
However it depends on what you want to do with the output voltage once it is output. It is a 20K pot so you are not going to be able to actually power anything from this signal.

Enter_Kratos

Thanks for the quick response guys.

Maybe if I explain my intended use it will make things a bit easier.
It's a bit of a pointless project but I have an electric train set which has a control box with a pot which allows you to control how fast the train goes. This control box has a max output of 12volts to the track. I wanted to hook something up between the control box and the track which will let me basically do what the analogue pot is doing but being able to program different timings to start off with with intent to build on top of this. I have an Arduino Duemilanove.

My idea was to use another chip which can pass through this max 12v and have various resistors on the different outputs to give me different steps. By controlling the chip with the Arduino I could change the speeds programmatically by telling it to output to whichever output has the strength resistor I wanted.

I hope I'm making sense. It may be a really silly thing but I'm just playing haha

Thanks

Grumpy_Mike

It makes sense but you will need an amplifier on the end of the pot in order to drive the required current into the train set. You can't do it from just the pot alone.

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