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    Diameter of imperial machine screws

    Thanks.t This helped a lot. t.
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    Diameter of imperial machine screws

    Thanks, It is definitely an US part. My local store here thought it was a 5/32 and I believed them. Might even be a #7 as you say. I probably need to measure it myself.... Edit: With respect to the list in my first post, does 2-56 then mean screw #2 with 56 threads per inch? and "4-40" is #4...
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    Diameter of imperial machine screws

    Dear Forum, I am currently trying to buy some imperial machine screws and bolts online, and I am confused with how the diameter is given. The website I am seaching (boltdepot.com) gives me these diameters but I don´t understand what is meant by i.e. "2-56" 2-56 4-40 6-32 8-32...
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    Low pass & High pass filters

    High pass: http://en.wikipedia.org/wiki/High-pass_filter Low Pass http://en.wikipedia.org/wiki/Low-pass_filter t.
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    Isolation Transformers and Electrical Safety

    Thanks again, uart...it becomes clearer but not 100%.. I need to read some more before I ask again ... :-) Another thing... with reference to my circuit in post #5, if there is a connection between any point on the secondary side of the circuit and Protective Earth, does the isolation...
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    Isolation Transformers and Electrical Safety

    Thanks uart, but still one thing is unclear to me... If there is a connection at point A (in my previous drawing) wouldn´t there be a difference in potential between the metal enclosure and Protective Earth? temu
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    Isolation Transformers and Electrical Safety

    Thanks...but then I have more questions... With reference to the diagram I have attached, there is accidentally a connection at point "A" making the "guy" touch a wire or enclosure that is conductive. Does the fact that the secondary part of the isolation transformer not beeing connected...
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    Isolation Transformers and Electrical Safety

    Hi, An isolation transformer is used in order to "safely" separate one part of an electric circuit from the mains. (description in http://en.wikipedia.org/wiki/Isolation_transformer" [Broken]) Still I have problems grasping the important concept of such a transformer. I have spent some...
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    ESD Protection

    was my first thought as well, but it had no effect... t.
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    ESD Protection

    Thanks for the tips and links. ...and yes, I meant 8kV (not 8000kv). The pdf you (berkman) linked was interesting, but due to tight time frames right now I have changed the switch for one with a higher rating. Hopefully it will work. t.
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    ESD Protection

    Hi, I have a switch connected to a motherboard. During ESD test with 8000kV (directly on the switch) the ESD spike caused my system to reboot, and I need some kind of surge protection betwee nthe switch and motherboard. I am not sure what I need to look for? Can anyone suggest a...
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    LaTeX Latex table problem :cry:

    what exactly is the problem? The table doesn´t appear as you want it to? regards t.
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    Proximity RFID Range Extendor

    Hi, Is that a passive or an active tag? t.
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    Medical electronics

    Hi, I remember Texas Instruments had some good application notes on ECG amplifiers. there are also plenty of books on the market. The "Webster" book as well as the one from "Enderle" (search for them at Amazon) are part of almost any biomedical engeneering course. They are good, but very...
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    Op-Amps for ECG Monitor

    Dear Forum, I would like to build my own ECG monitor. Does anyone have experience building one? Especially I am looking for recommendations on which op amps I can use. The ones I have found, like TI's ina122, ina 332 are both rather expensive (like 10 euro per piece) and hard tu find...
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    Coupling between tuned circuits

    Hello I have two resonant circuits (tuned to the same frequency) that are magnetically coupled to each other via two coils placed paralell to each other. (energy and data is transferred from one circuit to another) Now, I know that the coupling between the two can be overcoupled...
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    PU resin

    Dear group, Can anyone tell me what kind of material PU Resin is? Is resin a material or just a "spacification" of PU? regards t.
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    Superposition of magnetic fields

    yes, I do... (hard to explain without circuit diagrams but) I am working with magnetically coupled loop antennas. In my tests I have one transmitter antenna+a receiving antenna. Then a coupling coil consisting of 2 coil connected with a wire, so that one of the coils interfaces with the rx...
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    Superposition of magnetic fields

    Hi a short question: can I use the superposition principle for magnetic fields? reegards tem
  20. T

    Source (inner) resistance

    Actually I do include the antenna...(I am afraid to write antenna because I´m working on magnetically coupled RFID, not really antennas...)...I was actually wondering about how to depict the source... So if I use a 50 ohm resistor to model the load and the coax cable, is this resistor also...
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    Source (inner) resistance

    Dear Group, I need to simulate a HF circuit (matched to 50 ohm ) connected (via a 50 ohm coax cable) to a signal source with 50 ohm output resistance. Simulating this with e.g. Spice, should I use a 50 ohm resistor in series with the source? Does the fact that the source is matched to 50...
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    Pcb design software

    Dear Group Does anyone have experience with any good freeware for designing PCB? regards eirik
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    Loading of transformer

    dear all, When loading the secondary winding of a transformer, my textbook gives the following relationships: \frac{V_{sec}}{V_{pri}}=\frac{N_{sec}}{N_{pri}}\\ and \frac{I_{sec}}{I_{pri}}=\frac{N_{sec}}{N_{pri}}\\ Do these relationships hold also when the diameter of the windings are...
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    Q-factor in resonant RCL circuit

    Hi again, One additional thought....I think that the total reactive energy in the circuit is constant. At resonance the total energy swings back and forth between the capacitors and the inductor. Can it be that at one instant when the stored energy is at maximum in the inductor, the stored...
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    Q-factor in resonant RCL circuit

    Dear Forum, I am not sure how I can calculate the Q-factor in the circuit attached. (The circuitresonates at 13.56MHz and tuned to 50 ohm input impedance, thus the two capacitors) Is the Q-factor of the circuit simply Q = \frac{\omega L}{R_{a}+R_{coil}} ? I went through some examples...
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    Resonance in a coupled circuit

    Dear Forum, My question is to the circuit drawing I have attached. (representing a simplified rfid system, with "Circuit 1 being the tranceiver antenna, "Load" being a transponder and "Circuit 2" represents an additional circuit between) ... For optimal performance the circuit should...
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    Magnetic Field Lines

    I always thougth the "dotted lines" illustrating the direction of a magnetic field were only a tool for vizualizing this direction... Now I read that the definition of a weber equals 10^{8} field lines. So does this mean that the field lines really exist as discrete lines along the direction...
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    Magnetic Field Density

    Hi My textbook denotes the magnetic flux through a single turn loop as \Phi, and the magnetic flux density in the same loop as B = \frac{\Phi}{Area}. Extending to an N-turn loop the total flux passing through the coil is given by \Psi = N\cdot\Phi \leftrightarrow \Phi = \frac{\Psi}{N} ...
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    Impedance of load

    But this is an inductive antenna (for RFID), receiver and transmitter antenna are like a loosely coupled transformer. It does not radiate any energy at all. Does the coil still have any "impedance by itself"?? regards eirik
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    Impedance of load

    Thanks, But where do these 50 ohm come from ("...the antenna provides something close to 50 ohm real part at its design frequency...". The resistance of the coil is much less... If the circuit is tuned to 50 ohm, shouldn´t the input impedance be 50 ohm then?? Any reference to good web...
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