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Posts posted by slackjack

  1. Now lets say I wanted to make a digital voltage indicator to tell me my output voltage from the power supply and I wanted to power the indicator from my power supply. If it uses 5V would it be safe to setup some sort of voltage divider across the .1uF capacitor?

    The digital volt meter here has a range up to 1999. This is way more than I need. Are there any other low power ones that I can use with a smaller range that fits my purpose?

  2. I know that the 4k7 is a 5K-Ohm Linear Potentiometer from radio shack (part number 271-1714 as seen on http://www.uoguelph.ca/~antoon/gadgets/rs.htm ) Berfore I build my projects I always simulate using multisim or spice. Well on multisim I determined that a 5k pot only gives a max output voltage of around 14V-15V. However with a 10K pot, the max output is approx 25V. Mayb the schematic needs to be changed because I'm pretty sure I did the simulation correctly. I have determined that a 10K pot is the best alternative to the 5k pot.

    First graph is 5k pot and the second is 10k pot.

    I also noticed that multisim has LM317AH, H, K, LM, LZ. I tried the LM317LZ and LM317LM and both proved the same results. WHats the difference between all these LM chips stated above?

    I tried uploading the multisim file, but that file type is not allowed so I've uploaded as a JPEG.
    thanks again.




  3. Thank you.  ;D

    Does the LM317 amplify the input voltage in any way? If I decreased the transformer output voltage, then the max output volatge from the LM317 decreases proportionally?

    Another question - can I use a half wave rectifier instead? Since the LM317 is a voltage regulator, it should eliminate the extra ripple caused by the half wave rectifier right?

  4. I need to build a power supply to power my projetcs I am going to build. It should have an adjustable range from 0V - 32V. But I can settle for a range up to say 20V. Most of the schematics I found on the net have an input of 5V DC. Where I am suppost to get a constant 5V DC signal from ??? Its to get this 5V thats why I need to build a power supply.
    Now the second part of my question, is there any AC to DC power supply projetcs that take in 120Vac and meets all the requirements I stated above?

    --thank you :)

  5. I used the one from intelore. The trial version only allows a password length of 3. So I searched the net and got the crack. The brutforce method according to the program will take several hundred years to finish with a max passwd length of 7 (only lower case letters). So I selected dictionary crack, selected to use words with "V", and in a few seconds it found the password.

    Just letting you know what happend logan.

  6. Hunter. Is that Italian? Use a translation tool to go back and forth between the two languages. We usually like to keep discussions in English.


  7. How could I "lag" the phase 90 degrees with analog design?

    Well a wave the lags a sine wave by 90 degrees is a -cosine wave. When we integrate a sine wave, we get a -cosine wave. To do this you could use an operational amplifer configured as an integrator. The output voltage is:

    Notice that the integral has a negative (-) sign. Well the negative cosine and the negative integral will cancel out to give a postive output. To get the -cosine, feed the output to an invertor with a gain of 1.

    I'm not sure how good this method is at replicating distortions though
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