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  1. MP1

    fine Soldering Techniques info. pls.

    Here are some choices: http://www.abra-electronics.com/catalog/chemicals/gc39.html http://www.rpelectronics.com/Default.asp?Main=/English/OnlineCat.asp?Menu=/English/Content/Categories/CatM_85.asp%26Detail=/English/Content/Items/835-100.asp http://doityourself.com/store/6713317.htm...
  2. MP1

    MEASURING THD& on pc

    I do not work in that industry, but it is my understanding that high end eqipment for measuring such specs use transformers for attenuation. With a transformer, you get an exact replica of the sound wave but at a smaller level. Distortion in the sound wave would also be duplicated on the output...
  3. MP1

    Voltage Multiplier

    Here are some good links on voltage multipliers: http://www.tpub.com/neets/book7/27m.htm http://braeg.piranho.com/e_s/2theory/2_6_1_voltage_multiplier.htm Yes, all of the capacitors should be the same value. The circuit depends upon the direction of voltage from the rectifiers charging the...
  4. MP1

    MEASURING THD& on pc

    THD is a measurement done at a particular output impedance. You are expecting a certain number of watts at 4 ohms. You will see measurements on stereos that will vary such as 0.1% THD into a 4 ohm load or 0.1% THD into an 8 ohm load. If you change the output load, you will change the distortion...
  5. MP1

    fine Soldering Techniques info. pls.

    Another tip I will add: (1) Use liquid solder flux on the pins before you solder. You can clean them later with alcohol. It will leave a nice clean connection and cause the solder to flow faster. (2) If you get solder between the pins causing a short, use solder wick to absorb the excess...
  6. MP1

    Power supply for AMP in CAR

    Yes, that is exactly what I meant. The diagram in the article you have posted also gives a little better detail regarding the reason behind this. MP
  7. MP1

    Voltage Multiplier

    Current does not go up and down in a path. It remains the same. Perhaps I do not understand the question? MP
  8. MP1

    Labeling the project box

    For those who have been searching the web for the material I spoke about in the last post, I contacted 3M to get an update on the product. Here is the reply I have received today: ************************************ snip Thank you for your inquiry of 3M! The product you are searching for was...
  9. MP1

    Power supply for AMP in CAR

    I would not leave them out. Why should the current run through these 2N3055s equally? There is nothing there to cause it. There is no balance here. The resistors will cause current to flow equally through all of them. If 1 2N3055 is doing all the work because it has the least resistance, you...
  10. MP1

    Heeeeeeelp!!

    The heart of your circuit can be a 555 timer. A resistor and cap determine the time, so you can have the switches determine which resistance is used. I have attached a link or a tutorial on a post somewhere in here. Use the search function for 555 and you should find it. You should be able to...
  11. MP1

    What is a reasonable frequency?

    what do you mean by reasonable? Do you mean parts availability? Ease to build a circuit? Component count? Converting an AC signal to a DC signal is as easy as rectifying it and adding a few bypass caps. This is pretty much standard throughout the frequency range. MP
  12. MP1

    Led display Digital Voltmeter question

    maestrodamuz, I think you will want to relabel the voltages in and out of the LM317. I think you mean positive voltages here. ;) MP
  13. MP1

    Led display Digital Voltmeter question

    Here is a schematic and board layout that was donated by someone to the Eagle site. It is free to use. It looks like the project, but might be a little different. If you have the free version of the eagle, you can view it or even edit it to be what you want. If you do not have the free version...
  14. MP1

    Hitachi 2SJ50 datasheet &/or 2SJ55 X-ref.

    I do not have the data sheet, but I do have this information: 2SJ50 - 160V, 7A, 100W P-Mosfet in TO-3 case. 2SJ55 - 180V, 8A, 125W P-Mosfet in TO-3 case. and in case you have this also: 2SJ56 - 200V, 8A, 125W P-Mosfet in TO-3 case. Hope it helps! MP
  15. MP1

    MEASURING THD& on pc

    Although I know nothing about the Spectra software or your particular circuit, here is some general information regarding this. Total Harmonic Distortion is directly related to your amplification circuit. If you need to use an attenuation circuit, you will always have the characteristics of...
  16. MP1

    Power supply for AMP in CAR

    Cut the connection of the emitter to ground. Put 1 each between the emitter leg of the transistor to ground. You will not even know they are there as far as amplification of your circuit. But if they are not there and the system draws a lot of current, you could have a melt down. :D MP
  17. MP1

    datasheet for LA4440

    It is a discontinued chip from Sanyo. You can find the part number and description on their website, but they do not have the data sheet on the web. You can request a copy of it from them and they will e-mail it to you. If you do that, please upload it to this forum and we can all have access to...
  18. MP1

    Electronics Website

    Just come here and join us instead. You can post any circuits or data sheets that you would like. ;D MP
  19. MP1

    Power supply for AMP in CAR

    You will need some current limiting power resistors on the emitter side of the power transistors unless you are going to use MosFets. The reason this is done is because power transistors like the 2N3055 are not matched. Current will flow through them differently from one to the next. Because of...
  20. MP1

    Labeling the project box

    Here is a continue of the message that was started in the microprocessor area... For labeling, I have used a material in the past that was manufactured by 3M. This is a vinyl material. It is pretty thick, no worry about tearing or stretching it. You can also get it in a thin metal. I have used...
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