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  1. audioguru2

    3 Minute Timer

    Why 12V? A CD4060 is an ordinary Cmos logic IC that works fine with a supply voltage down to 3.0V. A high speed Cmos IC 74HC4060 works down to a supply voltage of only 2.0V.
  2. audioguru2

    DIY WBO2

    Why did you post a fuzzy schematic here and post the clear one over at ImageShack? Post the clear schematic here. Where is the -5V supply going to come from?
  3. audioguru2

    7.6MHz Crystals

    This Micromitter project explains what happens to the RF frequencies when a 7.68Mhz crystal is used instead of the 7.6MHz one in the datasheet for the BH1417 IC: http://electronics-diy.com/BH1417_PLL_Stereo_FM_Transmitter.php
  4. audioguru2

    How to use the ratiometric Hall effect sensor(UGN3503) in a levitron

    The sensor is at a right angle to the electromagnet and picks up both its North pole and its South pole that would cancel. Then all it detects is the strength of the permanent magnet in the levitating object which is determined by its distance. Maybe???
  5. audioguru2

    0-30 Vdc Stabilized Power Supply

    I would just buy two LCD voltmeter modules and add resistors for them to display voltage and current. The current meter should measure the voltage across R7 which indicates the current without reducing the output voltage.
  6. audioguru2

    0-30 Vdc Stabilized Power Supply

    An LCD voltmeter, ammeter project has already been done and was posted in our Projects Section only a few days ago. http://www.electronics-lab.com/projects/test/022/index.html
  7. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Yes. An N-channel Mosfet is turned on by making its gate about +10V higher than its source. Your circuit had the input going to +12V from the 4001 gate, so its source which is connected to the transformer goes up to only +2V. The other end of the transformer winding is connected to a turned-off...
  8. audioguru2

    Audioguru FM Tx

    This Andy guy says his FM transmitter has an RF output of 250mW. The other guy says that my FM transmitter that has nearly the same output circuit has only 10mW output. I think it is much more. I suspect that the output stage is operating in class-B or class-C and therefore has a pretty high...
  9. audioguru2

    Seismic Detector?

    Hi Ante, The project doesn't say one word about its sensitivity. It says to bury it in gravel. Then maybe it won't detect anything. Maybe only a nuclear explosion nearby. Ask Steven if he tried it to detect all the UFOs that fly around his place.
  10. audioguru2

    pyrometer

    Focus your IR beam with a lens. Surround the photodiode with opaque material except have an opening for the beam. Then it will not be disturbed much from light.
  11. audioguru2

    How to use the ratiometric Hall effect sensor(UGN3503) in a levitron

    Hi Shahriar, I didn't read the whole article but maybe it pauses the drive to the electromagnet then measures the magnetic field from the permanent magnet during each pause. It would be easy to use the pauses during PWM.
  12. audioguru2

    Seismic Detector?

    The project's output can be changed a little to drive a transistor that can turn on an alarm when there is an earthquake nearby, if you don't feel the vibrations yourself. It will probably also detect lightning's thunder pretty well. Maybe also kangaroos jumping along? Elephants? ;D
  13. audioguru2

    about light

    Yes, the frequencies of all the colors. No. Sunlight is white. White light contains many colors. Many colors are at many frequencies. A color chart shows the wavelengths of different colors. The wavelengths are related to the extremely high frequencies. Sunlight has many frequencies so a filter...
  14. audioguru2

    pyrometer

    You are trying to detect IR. IR is produced by heat. Guess what is 90% of the energy emitted by an incandescent lght? Hint: hold the light bulb in your hand.:D Hint again: Isn't sunlight bright and hot? IR photodiodes and photo-transistors are available in a black package that filters out...
  15. audioguru2

    0-30 Vdc Stabilized Power Supply

    Adding both trimpots is a good idea. I forgot that the current adjustment pot will try to make a max current of 4A which is way too high.
  16. audioguru2

    Power supply for amps

    Without the zobel network, the amplifier might oscillate and blow your tweeter. It will be noisy if it is oscillating, and maybe is getting hot. If the noise is a high frequency hiss, and it reduces when the volume control is turned down, then the noise comes from the source that feeds the amp...
  17. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Rufinus, Welcome to our forum. ;D It must be a big transformer. Use one of the 24V/5A windings, it is probably 48V with a center-tap. Insulate the other 24V wire. The voltage adjustment for your project will try to make the output exceed 24V and then settings higher will be full of ripple...
  18. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Hi Kachew, The center-tap on the transformer is supposed to be used to power the Mosfets while they conduct on each side alternately. Then each end of the transformer's winding is supposed to be driven by the drain of a Mosfet for the full battery voltage to be applied to the half of the...
  19. audioguru2

    Electronic Stethoscope 2

    Hi Soly, Last year, Con made a nice pcb layout:
  20. audioguru2

    22 W Audio Amplifier

    All amplifiers can make 10% distortion when their volume control is turned up too loud making the amplifier clip. But then the power number is bigger. With a 14.4V supply and operating bridged into a 4 ohm speaker, the TDA1554 has 22W output per channel with 10% distortion (s square-wave) or at...
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