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  1. MP1

    Links to Electronic Parts

    I have tried out their software and I have gotten pricing from them using the board layout program. The two quotes I got were not too bad, but were in the ball park with some other companies on the web. The big concern to me is this: I make all of my designs in their software and I am going...
  2. MP1

    author of the transformer article

    Kevin, when I mentioned that you might want to send a personal message to the author of the article, I was referring to the "instant message" feature. Click on his name in one of his posts and you will be able to send him a personal message from this site. MP
  3. MP1

    Lost with Ground, +15, -15 and 0 volts

    Bob, building from the schematic that Mike has provided would probably be the cheapest way to get this supply. You can purchase from surplus parts outlets. One such outlet is All Electronics. The highest cost will be the transformer. And here is an alternative: If you do not want to make your...
  4. MP1

    State Variable active filter

    Shmitt, here is the basic template for a state variable filter with gain. The 4th op-amp determines gain. All of the calculations are on the schematic. All you have to do is plug in your frequency and a few other values and you have a state variable filter. MP
  5. MP1

    Links to Electronic Parts

    Yeah, but you can only use the free layout program to have "them" make your boards. Takes the bubble out of free, wouldn't you say? MP
  6. MP1

    control a switch over the internet

    JamesTh777: Just a comment here about your tag line. I think that if all of the Christians could agree not to plug Christ and all the Muslims would agree to not plug Allah, as well as the Krishnas, Buddhists, etc. also holding back their views on life, then we could also expect the Satan...
  7. MP1

    Push button controlled Potentiometer? How?

    Here, try this. The Dallas digital pots are not that hard to figure. This is an application note from Dallas showing how. MP Dalls_Digital_Pots-app69.pdf
  8. MP1

    State Variable active filter

    Designing your own filters requires a bit of calculation. You need to know what you expect for damping factor, Q, bandwidth, and gain as well as the center frequency. The standard State variable filter design uses 3 op-amps, which I think will give you an inverted output. If your design gives...
  9. MP1

    regulators

    You would not refer to a regulator as a junction of two signals since the voltage at both sides of the regulator are from the same source. A junction would also imply the source comes from different directions, and the regulator is working with DC, which means direction of both sides of the...
  10. MP1

    IC question

    For some time I was making sure that I had the 4 corner pins for anchors and I left the other unneeded pads off my drawing as they were not needed. However, later I found that this was confusing to others as to which IC was there and left me the problem of making special parts drawings in the...
  11. MP1

    Free sample chips!

    I think that I should add: I am very grateful to these companies for providing samples for my prototyping purposes. We might rate them as fast or slow or grumble about package types available, but the bottom line is, they are free and an expense I do not have to provide to find out something is...
  12. MP1

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

    You might find it better to use this one for the specs you have described. http://www.electronics-lab.com/projects/power/027/index.html and start a new thread on modifications to this one, although from your description, it sounds like it might be ok as is. MP
  13. MP1

    DTMF transceiver connection

    Bascom AVR compiler has the dtmf output built in and also the A to D in your other post. The compiler is free to code up to 2K of the memory. You can download it from www.mcselec.com MP
  14. MP1

    0-30V varable volatge regulator

    gaark, if you can attach a schematic or a link to the circuit you are working on, it would be helpful to others to see what you already have in the circuit. I have noticed that the posts which get the most replies on this forum are those with an example attached. It makes commenting easier. MP
  15. MP1

    LM317 Variable power supply

    Hi Jandro, I have never seen anyone use this application. Perhaps the simplest way to do it would be to have the current change the intensity of light which activates a light sensitive resistor where the light sensitive resistor takes the place of the pot. You could make your own custom package...
  16. MP1

    PCRC-55 Humidity Sensor

    http://content.honeywell.com/sensing/prodinfo/humiditymoisture/ MP
  17. MP1

    Free sample chips!

    Yes, I know this. But the ones I have been requesting lately are not available in this package as samples. It looks as if I am going to spend a little time making adapter boards. ::) MP
  18. MP1

    PCRC-55 Humidity Sensor

    That is the nice thing about National Semiconductor. They usually print an application note somewhere. See Application Note # 256. http://www.nalanda.nitc.ac.in/industry/appnotes/Natsemi/AN-256.pdf MP
  19. MP1

    Free sample chips!

    I have noticed lately that all my free samples from Maxim have been very small surface mount rather than pdip. Anyone else getting this? Sure makes for hard prototyping. MP
  20. MP1

    Grounding circuit

    As Mixos has said, you would only use earth ground or case ground when the circuit requires it. Some circuits depend upon a floating voltage and will not work when the common of the circuit is tied to earth ground. If you would like to post a particular circuit or link, everyone could comment...
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