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cpwems
02-19-2005, 03:16 PM
I am trying to use the BS2 as a switch. Say have P0 and P1 create a short circuit with about 1.5uA (micro amps) going through it and potential of about 76mV. I would like this to be done programmatically, hopefully without having to use a bus switch or something like it, otherwise I know how I could use a bus switch. I have 5 lines that can short to a possible 8 lines for 40 combinations. Any help would be appreciated.

RickB
02-20-2005, 03:32 AM
It sounds like you are describing a multiplexer or crosspoint switch. Check out Maxim Dallas

http://www.maxim-ic.com/[url]

Rick

agentile
02-20-2005, 04:06 AM
I agree that you are trying to create a multiplexer. These are common, inexpensive, and easy to use chips. In fact, with a few logic gates, you can make one. I have included a link which shows how to make a 2 channel mux. You could easily buy a chip for a couple of dollars which will accept more channels.

http://www.play-hookey.com/digital/multiplexer_two_input.html



AG

cpwems
02-20-2005, 04:32 AM
Thanks for your guys help, but I need it to really act like a switch, something like TI SN74CBT3125D, where I can enable or disable to switch. I know I can use this actually device but was just wondering if I could do it using the BS2.

Bruce Bates
02-20-2005, 05:23 AM
CPWEMS -

The TI SN74CBT3125D can be driven by a Stamp, but a Stamp can not act in manner to replace such a device directly. Among other things, that device will support a constant current of 125 mA which is far in excess of what the Stamp current rating is.

The SN74CBT3125D is esentially nothing more than a transistor array. In fact, the Stamp uses a transistor array in its construction but it can not be used separately.

Regards,

Bruce Bates

agentile
02-21-2005, 01:33 AM
What if you use a multiplexer to drive a bank of relays? If you only need 125mA, you could just use a bunch of NPN transistors, and the output of the multiplexer can feed the base current of your transistors.



AG