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MP

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Posts posted by MP

  1. To change the board size, you just click on the corner of the board outline and move it to the size you want. However, if you have the free version, you will only be able to put your parts inside the size contraints allowed by the program.

    The reason you do not have VCC and GND connections is because you have not selected supply pins from one of the supply libraries. You choose a symbol for VCC and one for Ground, then connect these to the appropriate pins of the components. If you ran an ERC, it should have told you it was missing these connections. Also, you can select a solder pad from the solpad library to have a pad that you can connect the power lines to.
    For example: Once you connect a GND symbol to a Ground solder pad, you will see an air wire on your board layout going from the GND pin of the IC to the solder pad.

    MP

  2. I think I know what you want to do, now. If you can program a micro, you could connect a port line to the phone line through an appropriate transformer and have it listen for the high pitched tone after it gets the ring signal and produces an off-hook voltage on the line. Obviously, there will be no high pitch in a voice call. If it gets the high pitch, turn on the relay for the fax line. The fax will miss the first handshake, but the fax will always repeat the handshake if it does not get a response. After a very short time-out, if the micro does not hear the tone, then relay to the voice line. You will need to also figure out some routine to reset the micro back to a listening stage again. Perhaps with a little more code to determine when the phone is no longer in the off-hook mode.
    Does this sound like what you are trying to accomplish?

    MP

  3. You could use the UCN5804 outputs to turn on and off power transistors, but then you could also do this without even using the UCN5804 chip.
    It would be hard to relate the rating to oz/in. since the current ratings of the motors are what you actually calculate. Different gear ratios, etc. would give you different results.

    MP

  4. Yeah, like I said, you could just build your own system. These expensive ones pull the air through a HEPA filter which is pretty expensive in itself. Unless you do a lot of soldering, I would not worry too much about it. A small DC fan to move the fumes away from your face would be a plus.

    MP

  5. Inverters usually make a signal by switching the full potential voltage on and off with a transistor and feeding this directly into the transformer to limit the current loss. Your DC-DC converter would lose current in the conversion process, then would still have to incorporate the same charge pump circuit as an inverter to generate an AC waveform. I think you would not only have a circuit with less current, but would require more parts in doing so.

    MP

  6. Your relay is made by Panasonic. It is a 12 VDC / 5A relay. Here is a link to the data sheet that will help you understand the markings on the case and what they mean.

    http://www.alliedelec.com/Images/Products/Datasheets/BM/AROMAT/Aromat_Industrial-Control_7881012.pdf

    MP

  7. You do not want to breath the fumes from the flux. Yes, it is considered a carcinogenic. You can find this information in the Material Safety Data Sheet (MSDS). All manufacturers must provide an MSDS sheet if you ask for it.

    Here is the MSDS link to one brand of flux:
    http://www.ee.ryerson.ca:8080/~jkoch/MSDS_Sheets/MG_MSDS_835-liquid.htm

    Here is another:
    http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=18018039

    Take care when soldering. Use a bench mount fan that will pull the fumes through a filter if you have this available to you.

    MP

  8. The fax tone is only the handshaking signal. None of your fax message is on this tone. After this signal is transmitted and both devices have told each other they are connect through these tones, the data is sent. This data is sent on the same line as your voice, so there is quite a bit more to this than just isolating the fax tone to another line. You will need some type of smart circuit to make this happen. A few discrete components will not do it.

    MP

  9. I am certainly a believer in plenty of flux. Requires some alcohol clean up afterwards, but I always use plenty of flux. A gracious amount of flux when desoldering, tinning or assembling a board makes solder joints much nicer looking and much cleaner when you are finished. Gets rid of blobs and brightens up the look of the finished solder joint. A little trick I learned years ago when going through a course for MIL spec on soldering and assembly.

    MP

  10. No. It leaves a nice clean shining coating of solder on the wire. First dip the wire in some flux, then into the solder pot of melted solder down to the insulation. Only dip it for a second and pull it straight up from the pot. When you pull the wire out of the solder pot, it will have a nice even coating of solder because the bare wire was evenly heated. Using a solder iron will many times give you a solder blob at the end. This is because of the excessive solder on the iron. Most any agency that makes cables for their products will use a solder pot to tin all wires before they are soldered to connectors.

    MP

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