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 yyw794
 Posted: Oct 25, 2007 - 07:22 AM
 Joined: Jan 20, 2007 Posts: 69 Location: Mars
 in the research , i find the transducer's equation insists a negative resistance. it sounds strange to me, did you heard of that before? _________________Our Martians are beginning to learn AVR

 ka7ehk
 Posted: Oct 25, 2007 - 07:33 AM
 Joined: Nov 22, 2002 Posts: 14099 Location: Tangent, OR, USA
 Yes, Negative Resistance exists. This is the resistance seen looking into most oscillators when the resonator is removed. You can make negative resistance with an op-amp. Tunnel Diodes also have negative resistance. I do not understand your phrase Quote: the transducer's equation insists a negative resistance What do you mean by this. Jim _________________Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA There are some answers that have no questions.

 yyw794
 Posted: Oct 25, 2007 - 08:24 AM
 Joined: Jan 20, 2007 Posts: 69 Location: Mars
 for the research, someone have calculated that the transducer's (mechanical)characterist can be changed into electrical characterist ,like resistance, capacitance and inductance to be expressed. here, one of the parallel loop is a resistance which shows the negative characterist. by the way, we will paid the one who can teach us English,the salary is high in Mars, and we can settle with your registered permanent residence problem, and Hamburger freely everyday _________________Our Martians are beginning to learn AVR

 JohanEkdahl
 Posted: Oct 25, 2007 - 09:10 AM
 Joined: Mar 27, 2002 Posts: 22315 Location: Lund, Sweden
 Quote: we can settle with your registered permanent residence problem, and Hamburger freely everyday No offence but ... Intentional or not, this got me LOL!

 peret
 Posted: Oct 25, 2007 - 10:42 AM
 Joined: May 26, 2004 Posts: 2542 Location: Las Vegas, Nevada
 There's a very good article on Wikipedia. That's a link to the English version but no doubt the Martian language site also has an article. "The chances of anything coming from Mars are a million to one", he said.

 yyw794
 Posted: Oct 25, 2007 - 11:22 AM
 Joined: Jan 20, 2007 Posts: 69 Location: Mars
 I am the one of a million _________________Our Martians are beginning to learn AVR

 JohanEkdahl
 Posted: Oct 25, 2007 - 12:43 PM
 Joined: Mar 27, 2002 Posts: 22315 Location: Lund, Sweden
 Quote: I am the one of a million Nice to get that verified. We hoped and suspected that it was so, but where not certain...

 bobgardner
 Posted: Oct 25, 2007 - 04:23 PM
 Joined: Sep 04, 2002 Posts: 24113 Location: Orlando Florida
 Don't the Martians have a large colony in eastern asia with 2 billion colonists? _________________I ain't nobody's uncle, so don't call me that.

 ka7ehk
 Posted: Oct 25, 2007 - 05:38 PM
 Joined: Nov 22, 2002 Posts: 14099 Location: Tangent, OR, USA
 Back to the original question: Strange things do appear when one tries to find electrical analogs to mechanical properties. First, a transducer has very proper electrical characteristics. They can be measured. For a transducer, resistance represents (mostly) the electrical energy that is either converted to heat within the transducer OR is lost through the tranducer conversion mechanism (to outgoing mechanical energy). It is very possible that the person making this model (that is what it IS) is not interpreting energy flow correctly. If one expects power to flow in one direction and it really flows in the opposite direction, the resistance will appear negative. For example, if you think that the transducer should absorb electrical power, but really creates electrical power (perhaps from mechanical input), it will appear to be a negative resistance device. Jim _________________Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA There are some answers that have no questions.

 ka7ehk
 Posted: Oct 25, 2007 - 05:54 PM
 Joined: Nov 22, 2002 Posts: 14099 Location: Tangent, OR, USA
 By the way, this is the poster from China who has asked about AC coupling capacitors for oscilloscopes that don't seem to work, about ultrasonic transducers, and has said that he used cracked software because he is a student who cannot offord the real stuff. I am willing to try to help with genuine technical problems. Jim _________________Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA There are some answers that have no questions.

 barnacle
 Posted: Oct 25, 2007 - 06:36 PM
 Joined: Jan 03, 2006 Posts: 4865 Location: Hemel Hemsptead, UK
 All a martian needs to know about negative resistance in vacuum field effect devices... http://vintageradio.me.uk/novice/rfpentode.htm _________________Neil Barnes www.nailed-barnacle.co.uk

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