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  1. MP1

    Project Help

    eliminator, how are you with microprocessor chips? If you are familiar with them, then you might want to consider sending the information to the chip first, format the data in some way, then feed the data to the serial port of the PC instead. You will need other hardware to interface the...
  2. MP1

    Night rider scanner

    steven, since you have already built this circuit, could you please reply to the questions asked? MP
  3. MP1

    Power Supply +5v with Zener

    That was probably confusing... my last post was in response to reply# 21. I should have used the quote. MP
  4. MP1

    Light Switch

    siddharth, the statement in the previous post is not true. You need at least 6.5 volts to get a steady 5 volts out of a 7805, but there is no "low cut off voltage" where they will not work. You have a loss. If you supply 3 volts, you will get something like 2.5 volts on the output. This...
  5. MP1

    555 - 556 IC tester

    When did this become a forum where someone gets kicked around because they post a schematic which is a useful tool to them? You should applaud him for sharing. If you have helpful comments, that would be different. If you want to make fun of someone go to a different forum to do so. Hopefully...
  6. MP1

    Power Supply +5v with Zener

    The correct way to use a zener for voltage regulation is to pass the voltage through a resistor first, then to the zener. This is learned in first year basic DC electronics. Of course the zener got hot. MP
  7. MP1

    Power Supply w/ 3 Digit Panel Meter

    pmontone, the output of your power supply would connect also to the input of this project. Then you will have a digital display. There is a conversation about this project that will also give you pointers. You should use the search to find it or follow the link from the project. MP
  8. MP1

    741, TL071, LF351, NE531, TL061, TL081 IC tester

    Good job steven. Many on this list do not understand the salvage thing. MP
  9. MP1

    Power supply for AMP in CAR

    audioguru, in your comments to hotwaterwizard you mentioned that he should change the 2 diodes in the first transistor stage to resistors in his design. These transistors are connected as a darlinton pair. Adding such a resistor would disrupt the whole purpose of using a darlington pair. It...
  10. MP1

    Convert 0-30V 3A PSU to 5A or more

    No, I have not heard from Staigen for some time. Staigen, are you still dropping in? MP
  11. MP1

    Light Switch

    siddharth, you are correct. Once you know the light and dark resistances of the LDR, you can look at it like it is a simple resistor and use the voltage divider formula. The reason I like to use PNP transistors in such an application is because they are turned ON when the base is at ground...
  12. MP1

    741, TL071, LF351, NE531, TL061, TL081 IC tester

    The hobbyist does not have the luxury of knowing that 14,999 units are working so it must be a component failure and not a mistake in the board layout, design, or something else. The hobbyist also will put a lot more time into a circuit that would never be considered in a manufacturing...
  13. MP1

    Convert 0-30V 3A PSU to 5A or more

    Ante, this subject was started by mixos and I think he and staigen have a list of changes that they have made. You might contact him direct. He has been very busy with keeping up the site. MP
  14. MP1

    Posts

    Yes, you are gaining ground. What happens at 1,000? ;D MP
  15. MP1

    ORCAD and PS

    I think Orcad has a place on their website where if you register, you can draw and view files using the software on their website without a charge. You should be able to view a postscript file with Adobe pdf reader. Ghostview is another free program that will allow you access to postscript...
  16. MP1

    Car stereo amplifier output ratings

    ...almost everything on the motherboard of the computer you typed that on is static sensitive... ;D Just a little humor there. MP
  17. MP1

    Light Switch

    siddharth, my comment on not wanting to pop anyone's bubble was only in reference to a post recomending a transistor which was not the same type as on the data sheet (NPN vs PNP). You were on the right track to begin with. The one you posted and the data sheet. There are probably thousands of...
  18. MP1

    LCD panel

    Pins 15 and 16 are for your backlight on some display types and they are on the side with a couple of characters like K and L or + and -. Also, the voltage needed for the backlight might be +5 volts or -15 volts or anything in between. Different manufacturers use different voltages for the...
  19. MP1

    Unknow current in transformer

    Mikail, measure the resistance of each winding. This will give you the ratio. Use the basic formulas for transformers to go from there. DO NOT connect this transformer to mains until you know that it is the correct type of transformer. Be safe! MP
  20. MP1

    Power Supply +5v with Zener

    sure, try connecting a 9 volt battery to a 7805 regulator and see how long your battery lasts... Half of the voltage is converted to heat at the ground tab. It is not converted to current. It is only converted to loss. The more voltage you have to drop, the worse the problem. Regulators are not...
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