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  1. audioguru2

    Dont understand Schematic

    Hi Darkside, If you use the "source" output of the circuit to turn-on a 2N2222, its 47 ohm resistor will limit the transistor's base current to about 90mA which is much too high. Add a resistor of 1K to 10K in series with the base to limit the current to a reasonable amount. The source output...
  2. audioguru2

    Site's Clock

    Hi Mixos, Thanks for fixing the internet problems on your wonderful site. I have a small request for you, if you have a little spare time. That's it! The time. The site's clock is about 20 minutes fast, so i receive e-mails about replies that my clock says haven't even occured yet. Thanks...
  3. audioguru2

    3V LED Chaser project

    Hi Guys, Today I finished another (I've lost count) chaser project. This one is also "6V" like the ultra-bright blue ones and uses green ultra-bright LEDs. Wow, wow, wow and wow again! Is it ever BRIGHT! I thought the blue ones were bright. This one is amazing, like little green magnesium...
  4. audioguru2

    big ear, fm transmitter.

    Hi Dazza, Are you sweating down under too while I'm freezing up here? ??? ;D It's nearly noon and the sun is kinda low 'cause it's shining directly on you! (Except now you have night-time way around there) The operation of a tin can and string intercom is best understood if you think the...
  5. audioguru2

    12v lamp Dimmer lamp ideas?

    Hi Terje, Welcome to our forum. Don't hide your fantastic design in the mail, please post it here as an attachment to your reply for all of us to see.
  6. audioguru2

    big ear, fm transmitter.

    Hi Steven, I've given up with booze and beer. It was fun, but now I like to always see and think clearly. The "toy" big ears use a dish that is 60cm in diameter. Stadium horn tweeters use a horn (dish) even bigger. Maybe your dish is too small to properly reflect the long wavelengths of sound...
  7. audioguru2

    Dont understand Schematic

    Hi, Do you know about using a resistor in series with the transistor's base to limit the current? And a resistor to ground to turn-off the transistor?
  8. audioguru2

    If you are looking for good FM Tx, Look at this Link

    Hi Ante, I don't know much about Polar Bears. Maybe they don't eat penguins because they're friends? ;D The only times I have been far enough North to see no daylight in wintertime is on intercontinental jet flights. I also saw the opposite in summertime. Weird. My globe is only 8cm diameter...
  9. audioguru2

    big ear, fm transmitter.

    Hi Steven, An electret mic draws a fairly constant current through the resistor that feeds it power. Different part numbers of mics draw different amounts of current but most are 0.5mA. An electret mic needs at least 2V across it to work properly. You could measure the voltage of yours. Ohm's...
  10. audioguru2

    Dont understand Schematic

    Hi Darkside, Ante is correct, but it doesn't have much power to drive anything but a logic gate, due to its small output transistors and 47 ohm resistors. What are you going to drive with it? Additionally, the outputs operate normally open at rest, and activate when you touch the input. If they...
  11. audioguru2

    eq. or parametric analizer

    Hi Mark, Welcome to our forum. Does the sound system in your car produce 150dB? Kinda loud isn't it? Let's see. Most speakers produce a sound pressure of 90db/1W/1m. So with 10W would produce 100dB. 100W for 110dB, 1,000W for 120dB, 10KW for 130dB, ......, you're talking about a megawatt, you...
  12. audioguru2

    If you are looking for good FM Tx, Look at this Link

    Hi Ante, Polar bears don't eat penguins here because they are well fed and separate in the zoo. ;D Your Sverige is much further North than me. I am very close to the US border, about 43 degrees from the equator of our planet. Speaking of our planet, the only glowing I've seen is the Northern...
  13. audioguru2

    LM317 circuit doesn't supply enough current (only 20mA)???

    Hi MP, Measuring the current ahead of the regulator won't test anything. Of course it will equal the load current, plus a small amount to operate the regulator. A 2A (available) power source will provide only 20mA of current into a 20mA load. I asked him to remove the current-limiting resistor...
  14. audioguru2

    Question from a student about amps

    Thanks Kevin, I forgot to answer the transistor question. Capacitors and inductors create a phase shift due to time delay. I was taught ELI and ICE. The voltage leads the current in an inductor (ELI). The current leads the voltage in a capacitor (ICE). A coupling capacitor leads the current...
  15. audioguru2

    Interpreting Datasheets

    Hi Guys, I almost always design for "worst case", and use minimum spec's so that my designs always work with any part that meets the spec's minimum which is guaranteed. I was going to provide a sample circuit with a BC547 transistor that has a DC current gain from 210 to 900 and ask how you...
  16. audioguru2

    If you are looking for good FM Tx, Look at this Link

    Hi Ante, Hey, it loaded fairly quickly, maybe Mike fixed it. I like your new avitar. If the globe turns with the clock, I'll be able to see better where you are, and to see why NW Africa seems to be on fire! I'll look at it again in a few hours.
  17. audioguru2

    big ear, fm transmitter.

    Your screen shrinks from waiting so long for this site to load. ;D After I hit "reply", I ate lunch, watched some TV shows and even built half a project. I had a look and it still didn't finish loading. So I washed my car in the freezing cold outside. With my glasses all fogged-up, I typed...
  18. audioguru2

    If you are looking for good FM Tx, Look at this Link

    Hi Shahriar, Thanks for all the info about really high quality FM transmitters. Even with my shoes off (ran out of fingers), I gave-up counting the transistors, ICs, coils and caps on some of them. They have good pre-emphasis and some are stereo. There is even a list of FCC field offices so you...
  19. audioguru2

    "Soft" LED Chaser w/ acceleration?

    Hi Christoph, The 4 years old, expensive, 5mm, 630mcd (but today new ones are much brighter), 30 degree HP/Agilent ultra-bright blue LEDs that I've used are at 472nm. They are as blue as blue can be, I guess. The cheap Indian or Chinese copies that I got recently look the same. Good stuff! This...
  20. audioguru2

    "Soft" LED Chaser w/ acceleration?

    Hi Christoph, Wow, is this site ever slow! I've been watching TV shows and building my projects while it loads. I don't like narrow-angle LEDs that "cheat" on their intensity by focussing into a narrow beam. I try to select bright LEDs with at least a 30 degree angle. The RGB LEDs I saw project...
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