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ferrite beads
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ferrite beads

by tabula_rasa on Tue Feb 08, 2011 12:32 am

im making a link cable for my graphing calculator as to these plans: http://www.ticalc.org/hardware/cables/serial.html
i want to use a 1 foot cord between the serial adapter and the calculator. should i use a ferrite bead and if so how many and where on the cord. I only have 2
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tabula_rasa
 
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Re: ferrite beads

by Ramjet1 on Tue Feb 08, 2011 1:17 am

It never hurts to have a fer in the circuit but depending on application it might not be necessary. Typical installs I have seen on mission critical setups has the beads close to the input, ie. The end of the wire.
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Re: ferrite beads

by tabula_rasa on Tue Feb 08, 2011 1:26 am

thanks, i was thinking about putting one right in the middle but that seems like a better idea.
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Re: ferrite beads

by Ramjet1 on Tue Feb 08, 2011 6:38 am

The wire will act as an antenna for emi and rf. Putting it in the middle just cuts the effect in half. You want to kill it as close to the circuit input as possible. Scope it and you'll see it clearly.
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Please be positive and constructive with your questions and comments.