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  1. autir

    transformer questions

    1) What measurements can we make in an AC/AC transformer with nothing but a digital multimeter (and diodes, capacitors, resistances etc.)? 2) Suppose we have an AC/AC transformer rated 12V/800mA. Do the values refer to rms, peak or p-p? 3) After rectifying the AC with a bridge and connecting the...
  2. autir

    BNC connectors in 50 and 75 Ohm cables

    Problems problems problems. I visited two respectable stores. The salesman in the first shop told me that there are no 50- and 75- ohm BNC connectors. There is one type of connector which accepts all types of cable (regarding resistance values). The salesman in the second shop told me that the...
  3. autir

    LM78XX & LM79XX questions

    I went to the store to buy some .33
  4. autir

    TV cable connections

    gsmaster thanks ;D What are the losses of these devices?
  5. autir

    TV cable connections

    The impedance of the cable is 75 Ohm. By the way, if I am not mistaken, this is the impedance needed for satellite LNBs. Both televisions have good receptance. The point is that I am concerned regarding their receptance once water passes through the tape and into the cables. I would like to...
  6. autir

    BNC connectors in 50 and 75 Ohm cables

    Someone has a different opinion on this matter... http://www.levitonvoicedata.com/support/technotes/tech_note_detail.asp?tnID=175 http://www.levitonvoicedata.com/support/technotes/tech_note_detail.asp?tnID=176 As far as I know the TV signal is above 300 Mhz. Will I experience a (even small)...
  7. autir

    TV cable connections

    In order to give signal to two different cables, the TV technician stripped the cable coming out of my TV antenna and the two other cables. He then twisted all three cores together and all three nets/foils together. He insulated the junction with tape. This cabling is on my roof and has no...
  8. autir

    BNC connectors in 50 and 75 Ohm cables

    I have removed the TV socket in my wall and installed a BNC connector in the end of the cable. It is a typical 75-Ohm cable. The BNC connector was bought for usage with RG58 50-Ohm cables. Will I experience problems?
  9. autir

    LM78XX & LM79XX questions

    Are the values of the capacitors of significance? The absorbing of sharp transients in the output line is improved with the capacitance; a bigger capacitor would perform much better. Why just 1 pF? Similarly for the input capacitor (is it an RF-lowpass filter to filter out AC?).
  10. autir

    LM78XX & LM79XX questions

    What is self-oscillation? ;D How can a capacitor improve transient response? How can a capacitor minimise the effects of load variation?
  11. autir

    LM78XX & LM79XX questions

    It is mentioned in the datasheet of the LM78XX series that for the standard operation the pins 1 (input) and 2 (ground) must be connected using a capacitor of 0.33
  12. autir

    Simulation in Linux?

    Thanks for the feed EnigmaOne. But I am a minimalist... using Slackware and fluxbox WM. No Gnome, KDE, apt-* utils. And I will not change my distro ;)
  13. autir

    Maximum current for AC/DC adaptors

    Alun thanks for the reply. I know about the different types of ac/dc conversion, my question was how the change in load can alter the output voltage. Does it depend on the internal resistances of the AC/AC transformer itself?
  14. autir

    Strange observation

    Check these out: http://www.electronics-lab.com/forum/index.php?board=21;action=display;threadid=2308 http://www.electronics-lab.com/forum/index.php?board=21;action=display;threadid=2336 Regarding the slow decrease of the voltage when you unplug the adaptor, it is absolutely normal. It is a...
  15. autir

    Maximum current for AC/DC adaptors

    Are there regulated and unregulated AC/AC transformers? Or are all transformers unregulated and the regulation of the voltage depends upon something else (a circuit, perhaps)?
  16. autir

    Simulation in Linux?

    gEDA sucks! A needed B, B needed C... installed 20+ different things, some would not compile, no uninstall could be done in some of them, got angry, formatted, reinstalled Linux. :( I'll try Xcirquit for now.
  17. autir

    high voltages

    gotcha! :P
  18. autir

    Voltage regulator + current amplifier?

    I have read that voltage regulators dispose of surplus power by dissipating it as heat. I have an idea, most probably something is wrong but I would like to ask you. What if the regulator supplied just a small amount (~10mA) of current to a current amplifier which would provide the "real"...
  19. autir

    Simulation in Linux?

    Ante I work as a systems administrator in an informatics laboratory in the University of Athens. When I talk with the other admins I always see strong opinions - some love Win, others hate it. And most of these persons are most educated and extremely skilled in operating a variety of machines...
  20. autir

    Maximum current for AC/DC adaptors

    (Why was the previous topic locked, gentlemen? ???) From what I have read I have realised that the current listed on most unregulated AC/DC adaptors is the one needed for output voltage to take its nominal value. How can I determine the maximum current rating for an adaptor (without destroying...
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