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  1. MP1

    newbie confused with voltage dividers

    terrakota, The current is the same in a series circuit, but it equals the sum of all branches of a series parallel circuit. I think you already understand this from your explanation. However, an LED is a different calculation than the normal series parallel resistor calculations. Here is an...
  2. MP1

    free schematics links, great page

    Where are the free schematics on that page? The subject line of this post says "free". All I see are ones which cost money. I would never pay for a schematic. MP
  3. MP1

    STI5518

    Did you look in the past posts in the data sheet request area? MP
  4. MP1

    Auto PowerOFF Power Supply!

    It would be simpler to find a smarter teacher ;D However, if this is not possible, you could write a clock program and use a micro port pin to trigger a relay on or off. You can also find timers in electronics stores which will allow you to set the on and off switch to different times of the...
  5. MP1

    Inductance Calculation

    Perhaps pulsed DC. You need current change in an inductor so that the varying flux (magnetic flux) can cut across to the other inductor (mutual inductance). MP
  6. MP1

    [ARTICLE] How to rebuild a Li-Ion battery pack

    The project article looks very nice. I trust you now have more life in your laptop. I recently purchased a laptop on e-bay. Got a good deal at $200, but then it needed a battery and that cost another $100... MP
  7. MP1

    Making an electric furnace.

    ;D ;D Midnight engineering? ;D MP
  8. MP1

    Bigginers Handbook

    Perhaps with this many requests you should zip it and upload it to the files section. MP
  9. MP1

    MOVED: DVM??

    Not a project. Moved to theory discussion. http://www.electronics-lab.com/forum/index.php?board=15;action=display;threadid=2565
  10. MP1

    Led display Digital Voltmeter question

    I have merged some of the old Digital Voltmeter conversations found in another area into this thread. Go back to page one and browse through the messages of this thread. You will find the answers to these questions in the past posts. MP
  11. MP1

    Led display Digital Voltmeter question

    The discussion regarding the final corrections were in another area. This happens when someone starts a new topic instead of posting in the same thread. I have merged that discussion into this one. Go back through the pages of this discussion and you will now find all of the information. MP
  12. MP1

    Making an electric furnace.

    I have never considered using electric for doing so. The expense is too high. I have only used gas type furnaces for foundry work. (I have never seen an electric one). But then, I do not have much experience in this area. I do, however, have a wave soldering machine which is electric. It has two...
  13. MP1

    Logic Gates IC Chips

    This would be the same as my description above for a NAND gate, except the logic table is different. When you see a logic zero, the voltage is 0. When you see a logic 1, the voltage is full scale. In the case of my example above, a logic 1 would be 5 volts. MP
  14. MP1

    COLOR DETECTOR

    Here is also a link that might help you in measuring light with regard to color frequency. http://www.sensorsmag.com/articles/0500/26/main.shtml MP
  15. MP1

    call for articles

    Perhaps you would like to add a link to this site in your e-magazine? There are many articles and projects here as well. MP
  16. MP1

    How to tell if an old electrolytic cap is good

    There have been a number of discussions on this site about electrolytic caps going bad from drying out with age. From my experience, it is only in extreme conditions or in very old equipment that one would have this worry. There have been several instances of bad caps entering the market from...
  17. MP1

    Need help in fixing lexmark printer

    Felto, You asked this question under the opto sensor topic. Please also look there for my reply. MP
  18. MP1

    Slotted Optical Switch

    For this type of testing. everything in the circuit will effect the readings unless you pull the device and test it. This is not necessary. If you lift pin 3 to insure something else in the circuit is not pulling down the voltage, and then you measure 14.6 volts or more between pins 1 and 2 but...
  19. MP1

    Slotted Optical Switch

    Felto, This is a new subject. You should start a new topic or others might not read your question. Here is the data sheet for the 7812. It has the pin out and the electrical characteristics. Basically, the middle pin is ground and the right pin is the 12 volt output when you give the left pin...
  20. MP1

    Slotted Optical Switch

    Felto, Perform a search for opb optical switches. Here is a link to an application note: http://www.optekinc.com/pdf/App%20Note%20213.pdf#search='opb%20optical%20switch' One side has an LED and the other side has a photo transistor. Making or breaking the light path turns the transistor on or...
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