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harsh

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Posts posted by harsh

  1. hard to retrive password

    in Feedback/Comments

    Posted

    i just had a heck of a time retriving/changing my password
    maybe it should be fixed ?
    others probably would have given up
    the problem was the link in the email sent to my address was not complete
    ie the underlined part only covered part of the whole link , thus when clicked on it sent me back to the same page that i requested the change from.

  2. help, help, help, it's too hot

    in Electronic Projects Design/Ideas

    Posted

    J-type thermocouple

    Definition:

    A thermocouple best suited for measurements in the 0 to 480 degree © range. The positive conductor is made of iron, and the negative conductor is made of constantan.

    May i put my two cents in here ?
    mrtrhs, how about a radioshack thermistor? i realize that you may not have a "shack" around the corner ,but the thermistor ,in my opinion , is the way to go.
    You could set up a voltage divider using 5V as a supply voltage.
    Just a suggestion.. ;D

    Oh ... What temperature range are u thinking of measuring?

  5. Another 4watt Transmitter Question

    in Projects Q/A

    Posted


    * The inductors is air from wire of coaxial 75W or other 1mm roughly


    i believe this should read 75 "ohms' not watts..
    so u should just take the center conductor out of a coax cable, and wrap it around a 7mm diameter rod and u are good to go.
    i am not sure if u can substitute a 2n2222 for the 2n2219 transistor.
    i am sure somone else will know that.

  16. Help a newbie out!!!!!

    in Theory articles

    Posted

    hi nestorages,
    this is the deal, u cant use a transformer with Direct Current ( DC )from a battery.

    here is why

    a transformer only works with Alternating Current ( AC ).
    if you were to touch the battery to the windings of the transformer and removed it ,u might notice a little spark, that spark is caused by the collapsing magnetic field.
    same principle as the automotive ignition system.
    hope this helps..

  19. xp has debug

    in Electronics chit chat

    Posted

    Warning !! USING DEBUG CAN SERIOUSLY MESS UP YOUR SYSTEM AND THIS MESSAGE BOARD IS NOT RESPONSIBLE FOR ANY DAMAGE YOU MAY CAUSE !!
    When using debug you may have to reboot so it is best to try it with no other programs running..


    with that said debug can also be a lot of fun.. for example it gives u the ability to " poke " in small assembly programs and run them.. and watch the registers change..BUT be warned.. see above.


    i didnt think it had debug.
    but i just tried it and it worked..
    start -->all programs --> accessories --> command prompt..
    at the prompt type --> debug and hit the enter key
    when debug is working it will show a line with a blinking underscore--> --_
    at this point u can see the internal registers by typing r then enter..
    there are many other commands that debug has if anyone is interrested i could post them also.

    to Exit debug type q enter.
    to Exit command prompt type exit enter.

    Warning !! USING DEBUG CAN SERIOUSLY MESS UP YOUR SYSTEM AND THIS MESSAGE BOARD IS NOT RESPONSIBLE FOR ANY DAMAGE YOU MAY CAUSE !!

    post-3431-14279141706587_thumb.jpg

  25. Decision making before micro processors

    in Electronics chit chat

    Posted

    i need a circuit to turn a relay on and off.
    the relay controls 12 volt fans.

    the control condition is heat, which comes from my refrigerator, and the fans vent the heat away from the cooling fins.

    so when frige comes on i would like to have the fans come on shortly thereafter.
    and when the frige goes off i would like to have the fans go off.

    i could even do it without a processor using an a/d converter, but i dont even want to use an a/d converter, seems like overkill.

    the circuit should be simple , maybe using an op-amp ,maybe.

    options:
    thermistor with changing resistance..

    but how do i turn a changing resistence into what i need ?
    driveing the relay isnt a problem assuming i have a signal to drive it with.

    so i have a changing resistance ,and i am working with 12 volts i think the relay is 12 volts also

    Thank you.
    william

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