What is the maximun AMP and Voltage an SX can output

cameron

What is the maximum AMP and Voltage an SX can output with all pins set as output or does it not make a difference?.

Thanks,

Cameron

Bean

· Here is a link to the datasheet. http://www.parallax.com/dl/docs/prod/datast/SX20AC-SX28AC-Data-v1.6.pdf
· According to page 40, the maximum current for one pin is 45mA. With a total of 130mA for the whole device.
· The maximum voltage is 5.5volts.

Bean.

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cameron

Thanks Bean, for your help today. Have a great weekend.

cameron

Hi Bean,

In simple words can you explain to me how to increase the AMP I can get from one SX chip pin. I have heard that you can use a transistor but I don't know how to go about this any help in this would be a great help.

Thanks,

Cameron.

PJMonty

Cameron,

Why not just explain what you're trying to do (in detail) so that the folks here can help you. Generic questions get generic answers, and it sounds like you have something specific in mind.

Thanks,
PeterM

Bean

Cameron,
How many amps do you need ? What are you trying to drive ?
You need to lay your cards on the table or else we just keep going back and forth playing twenty questions...

Bean.

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"Educate your children to self-control, to the habit of holding passion and prejudice and evil tendencies subject to an upright and reasoning will, and you have done much to abolish misery from their future and crimes from society"

Benjamin Franklin
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
www.hittconsulting.com
·

Mike Green

Many of the Stamps use an SX processor, so any examples of driving high voltage/high current devices using a Stamp also apply to the SX in general. Have a look at some of the tutorials in the Stamps in Class series. Start with "What's a Microcontroller" and the StampWorks Manual. All of these are downloadable through the Downloads menu item on the main Parallax website.

There are also a wide variety of articles in the Nuts and Volts column, also downloadable using the Downloads menu item.

cameron

Hi I am sending a 5Volt signal to a power board to an MOC3041 OptoIsolator I think thats what it is called (its a led switch which directs an AC current to drive an AC main motor) I am able to drive the small motor using the same process. However the main motor MOC3041 requires 500 mA.

Does this make more sense, I am new at these things so if you need more information let me know.

Thanks,

Cameron

cameron

I am pretty sure I can use the Parallax ULN2803A Darlington Array but I dont want to send away for that because I am in Florida I would first like to know if the is another way I can do it first.

Oh and thanks to everyone for your help. This is the first time I have used a Forums and I am very impressed with the help I get thank you very much for your time.

Mike Green

The MOC3041 is a Triac driver. It can switch small amounts of AC (like maybe 60ma), but really is intended to switch on a power Triac as shown several pages into the datasheet. There are other similar switches, generally known as "solid state switches" or "solid state relays" which include the Triac and some other components to reduce switching noise and the like. All of these use an LED as part of an optoisolator. All of these use a current roughly 5-20ma to drive the LED. Any electronics parts supplier like Jameco, Digikey, or Mouser carries lots of these in varying current and voltage capacities. Any SX pin should be able to drive such an LED using an appropriate series resistor (which depends on the power supply voltage). For a 5V supply, a 330 to 470 ohm resistor is usually used and provides roughly 8-10ma through the LED. As Bean mentioned, there are current limits for each port (group of 8 I/O pins) and for the whole microcontroller. With 10ma for each solid state switch, you could certainly control 8-10 solid state switches before starting to worry about total current draw.

Crydom is one common manufacturer of solid state relays. Most of these include the current limiting resistor, so you'd just connect the "+" terminal to the I/O pin and the "-" to ground or the "+" terminal to +5V and the "-" to the I/O pin. The other two terminals are the AC switch and you'd connect them in series with your motor.

Post Edited (Mike Green) : 5/14/2007 8:24:27 PM GMT

cameron

Thanks Mike Green,

However the power circuit must be drawing more current from somewhere else all I know is that the current it needs is 500mA so I need a way to increase this, any suggestions?

Cameron

Mike Green

I can't make any suggestions without a schematic diagram showing how you've connected everything (and information about the various parts including their expected current draw).

cameron

I don't have the schematics because I am using someone else's circuit, but do you have any idea how in any project you could increase the AMP in one of the chips by using a transistor or by some other means. Any help would be greatly appreciated.

Bean

Here is a sold-state relay that is meant to be connected to microcontrollers.
You should have no problem running your motor from this SSR.

http://www.efx-tek.com/topics/crydom.html

Bean.

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"Educate your children to self-control, to the habit of holding passion and prejudice and evil tendencies subject to an upright and reasoning will, and you have done much to abolish misery from their future and crimes from society"

Benjamin Franklin
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
www.hittconsulting.com
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