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  1. M

    car battery charger

    Perhaps he could use a Gate Controlled Switch instead. Those can turn off, unlike a SCR.
  2. M

    Motorola Hi-Fi power amplifier

    I wouldn't put an ammeter on a very low output impedance amplifier if its offset voltage wasn't zero. The only current limiter is the fuse. (the fuse in your meter) I wouldn't either. That's not what I believe he's telling us. It would seem he wants one lead of the ammeter to be connected to...
  3. M

    Motorola Hi-Fi power amplifier

    I think the author makes an error when he says to put a current meter on the output and adjust the trimpot for zero current reading. I think the adjustment is to reduce offset voltage at the output to zero so there isn't a DC voltage on the speaker. The instruction is ambiguous at best. He...
  4. M

    RC time constant

    In the mathematical sense, C is completely arbitrary. Use it to turn the general solution of a differential equation (of which there are an infinite number) into a particular solution that depends upon initial conditions. In the electrical sense, since you're dealing with time varying signals...
  5. M

    To Find Working transformer

    You can use this handy little tester to check for shorted out coils on an iron core xfmr. Simply close the momentary contact switch, release and see if the neon light flashes. If it does, then you don't have any shorted coils. If it doesn't flash, then you likely have a shorted coil that's...
  6. M

    DIGITAL STOPWATCH(Chronometer)

    One question: why? It'd be a helluvalot easier to write a graphical program to put the chronometer right on the screen. The PC, itself, already has time and date information, which can be accessed via library functions. The FOX Toolkit already has a seven segment display widget. It really...
  7. M

    240W Class-D surface-mount amp IC

    diyaudio.com There's a site that'll keep me busy for awhile.
  8. M

    240W Class-D surface-mount amp IC

    All car amplifiers are rated in Whats where the amp is clipping badly to make the numbers much higher. I caught that in the original post, and figured the whole thing was a joke site. I went through all 26 pages on that, looking for the punch line before realizing that it wasn't a satire...
  9. M

    240W Class-D surface-mount amp IC

    Take a LQQK at those specs. 10% THD?! It takes some set of brass cojones to call this "high fidelity". That thing might be good for a PA system or, perhaps, an AM modulator for a ham rig (for those who still haven't made the move to SSB -- how many of those are left anyway?) where fidelity isn't...
  10. M

    New.....I need help on replacing a fuse, please.

    The power input on a tube radio is usually a multi voltage input transformer. And a transformer is an inductor so yes the frequency matters. I am just not sure how much! Take a LQQK at the general transformer equation: VN= 4fSB where: VN: Volts/Turns ratio f: Frequency (Hz) S: Core X-section...
  11. M

    Screen Resolution

    It had nearly double the bytes of your schematic but looked like nearly 4 times the pixels. I counted 12 steps on the ramps of your opamp symbols but 19 steps on mine. I count 12 as well. Looks like the only alternative is to re-draw the whole thing. Oh well... My previous post got deleted...
  12. M

    Screen Resolution

    Can you convert an original bit-map to a GIF? That's exactly what I did. I made both the *.jpg and the *.gif from the same original: a *.bmp image I made a long time ago, when I still used Windows. It looks like you converted the JPG to a GIF. I didn't. I really can't explain this since I'm...
  13. M

    Basic Car Audio Electronics

    Haha! Yep, and hopefully those idiots will listen. They'll be lucky to be able to hear anything, let alone listen.  :o Every time I hear one of those damn things, I imagine the owner spending the rest of his life going: "What'ja say? What'ja say? What'ja say?" Then I feel better.  ;D
  14. M

    Screen Resolution

    May be it's a screen resolution difference? It still looks good here. Anyway, here's a *.gif. Let's see if that works better.
  15. M

    Hi Friend

    Just like I stated: lots of possible implementations.  ;D
  16. M

    741 Offset voltage problem

    Here is your problem. If you are going to operate the 741 from a single-ended power supply, you need to maintain 1/2VCC at the inputs. If you don't, then you get that lock-up problem. Here is a solution that I used in one of my projects:
  17. M

    Hi Friend

    I need some advice about current converter. How to converted 24Vdc to 19Vdc. A series pass regulator will get the job done. There are lots of variations on the theme. Here is an example.
  18. M

    project help?

    I want to make a circuit where we speak into a microphone and the amplitude of our voice will be reflected in a series of LED lights. For example, if we yell all 10 lights would light up, and if I speak normally, only 2 would. Any help would be appreciated. Thanks. So, basically, what you want...
  19. M

    Need Ic which can Enable Its outputs One by One!

    I need an IC (i.e. 74XXX Series) with 8 or more outputs. The outputs will be enabled on by on after each other when I trigger the Clock pulse Input. the important note is that the outputs should stay enabled until I reset the IC. I never heard of a 74XX that would do that exact thing. However...
  20. M

    New member says hi!

    I'm also taking radio communications and it blows we haven't even covered transmitters and receivers properly. I did think of doing an extra year to get an HND but I'm sick of all the non-electronic bs we've had to cover this year and I have a feeling that the next year would be worse so I'm...
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