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Xenobius

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Posts posted by Xenobius

  2. Strange Screening Problem

    in Projects Q/A

    Posted

    Hello all,

    I have built this circuit http://www.electronics-lab.com/projects/sensors/008/ and it worked. However I have a problem. I am using a DC adaptor to give it 12v and so im not so sure if its pure dc. The problem is that, IF I touch the positive metal part of the power supply, the circuit works perfectly... if I remove my finger from the positive of the power supply, the RED led (of the circuit LED1) turns ON until I touch the + again.

    Could this be a filtering problem of the power supply? I put 10uF and 68nF in parallel across the power supply but no luck.

    Thanks all

  10. Variable AC Dummy Load

    in Electronic Projects Design/Ideas

    Posted

    Nice to see you are interested. Well I am working with 230vac at 50hz.

    I have some solidstate relays which I need to load to test them. I know its expensive but I still would like to give it a shot here

    Thanks guys!! Looking forward to your help as I am lost hehe  :D

    Will post some pictures of it when I finish it (if I start it) hehe  :P

  11. Variable AC Dummy Load

    in Electronic Projects Design/Ideas

    Posted

    Hi guys, I am looking for a circuit so that I can build a variable dummy load AC not DC. Could anyone help out?

    I am currently using rows and rows of 200W bulbs .. but they heat up too much. Any other IDEA apart from Resistors which are really really expensive?

    thankyou

    PS. I did find a DC dummy load here in the forums but as said.. its DC not AC

    THANKS

  12. Computer IDE Switch

    in Electronics chit chat

    Posted

    Hmm No no I need to use the motherboard IDE Sockes! :p all PCI Slots are booked  :-X

    I was reading in that article that if you remove the power of a hdd, the bios will still detect it.

    Could anyone tell me which pins does the bios use to dedect this?

    thanks guys

  13. Computer IDE Switch

    in Electronics chit chat

    Posted

    Dear friends,

    I have a problem right now. I have 2 hardisks in my pc and 3 optical drives. Since I use all of them, I have to turn off the computer, unplug a cd-rom and plug in my dvdrom and turn on the computer again.

    Is it possible to make a switch not on the power but on the IDE cable so that the computer will literally think the drive is not connected? altghou i will still leave it connected?

    For example I was thinking.... I will cut only the data wires of the ribbon cable and make a switch to connect/disconnect them.

    It this possible? .... I know there are 4 - 6 wires which the computer uses to verify if the cd-rom is connected and if i cut those, It will help a lot

    thanks

    A LOT

  17. 19v 5A PSu

    in Electronic Projects Design/Ideas

    Posted

    Hello, I would like to build my own Laptop Psu because the original one broke. Could somone kindly enough point me to a Circuit of a Fixed PSU which gives me 19v @ 5A ??

    ALSO since a PWM Power Supply does not heat up that much, is it good for a Laptop??

    thanks a lot


    PS.. Speaking of PWM.. I have a motor which takes 24v @ 14A. Does anyone have a circuit to controll such a motor?? the supply of this motor is two large batteries with 12v each in series.

    Thanks a lot.

    Xenobius

  19. Magnet Wire or Enameled Wire?

    in Theory articles

    Posted

    Ok this is stupid ... But i must ask.. Could somone help me by giving me IDEAs on how to make the coil ROUND flat on the table not as we usually see it wound on a rod.

    I am trying al sort of stuff but the coil just doesn't come roundish ... any ideas on how to make it perfectly round with perfect spaces in between? maybe a smal mechanical machine ? thanks

  21. Magnet Wire or Enameled Wire?

    in Theory articles

    Posted

    I would like to build a circuit which has a coil and it stated that it should be "FLAT MAGNET WIRE" . Ok I understand FLAT .. (any wire I choose must be bought Flat and not round and infact I found on the internet which is Flat) but I was searching a reliable shop and it stated that Magnet wire is a term used to show that the wire is going to be used in Winding transformers ..... As far as I know Transformers are wound with normal copper wire with insulated yellow stuff (forgot its name)

    Anyways .. Could someone tell me what REALLY is Magnet wire? because I was thinking that the wire itself is made of magnet material and if you put a small piece of magnet wire near an iron, it would be attracted just like a magnet would do with a piece of iron... but all of a sudden I am thinking it is just a normal wire with insulation.

    Thanks for the help

    Cheers

  22. 12v Relay on When Car Running

    in Electronic Projects Design/Ideas

    Posted

    I do not know how to shut of the engine with the help of a switch but about the cellphone, My friend has just built a unit which switched on and off when you call.

    You will need a cellphone with a  NEW simcard. Remember you will not be able to use the cellphone again as you need to modify it and also you need a simcard which it totally new and which NO ONE knows aout because if somone calls you the relay would switch either on or off depending on the state it was.

    If you can afford the rent of the simcard and the cellphone, you may ask again.

    The circuit works as follows. when the cellphone receives a ring, it will give a signal to the microphone, only the microhpne is now connected to a circuit to switch either on or off. The circuit also ENDS your call automatically too.

    I do not have the circuit but it is easily done because I have seen it and it only needs a flipflop and a 555 timer and some components to aid them.

    cheers.

  23. Magnet switch and smart card reader

    in Electronic Projects Design/Ideas

    Posted

    Hello people, I would kindly like to ask somthing which is giving me a lot of trouble finding on the web.

    I am trying to make a small cupboard with strange methods of opening it!!

    I was thinking about making somthing from inside the wooden door at a random place only known by me, and when I put some sort of magnet from outside, the sensor from inside would sense the magnetism and give a logic 1 (5v). Than I would insert a smart card in a slot and if verified OK, would give me another logic 1 (5v).

    Than with the help of an AND-GATE, I would have 2 logic 1 and an input and the AND-GATE would give a logic 1 switching a transistor and the transistor switching a relay which would give supply on an electric lock and the door would open.

    The third problem is about the AND-GATE because as soon as I remove the magnets the logic would go to 0 (0v) and I would not have enough time to open the door.

    SUMMERY: I was thinking of making 2 of these magnetic sensors and 1 smart card reader. I would kindly like to ask somone to help me with the megnatic sensor, the smart card circuit to read a smart card and a person to write me a code so that the TIMING could be adjusted so that I would have 4 seconds chance to put all 3 sensors into logic 1. Otherwise it would reset and I have to start again. And give me 4 seconds chance to OPEN the door. Once the door is open, the pic would reset and the electronic lock would close, so that when I am finished from putting stuff inside the cupboard, I just close the door and everything would be closed and reset and would need me to input the 3 logics AGAIN if I need to open the door.

    THANKS EVERYONE for the help. I really appriciate and am looking forward to put up a PDF file of the WHOLE finished thing when it is done!!

    THANKS AGAIN

  24. Telephones!

    in Electronic Projects Design/Ideas

    Posted

    thanks a lot everyone for helping me out.. But I still do not know which one I need to build from these in the list.

    just to remind you. I have 2 different telephone numbers 1234 and 5678 and I need to connect with the other one just like calling normally BUT without the charge.

    These 2 numbers are in the same house so I can talk to my mother from upstairs to downstaris..

    In other words the telephone lines are both here infornt of me !! All I want is a thing to connect them together in a way that when I am busy on the line NO ONE can listen to the call and they cannot phone me... they only succeded to contact me when I am not using thep hone. so if I am on thep hone they would not interrupt me.. and vise versa.. thankyou !!

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