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  1. audioguru2

    How to transmit music from PC to music system wirelessly...??

    Buy an MP3 to car radio transmitter. If it is stereo and is good, then it will have da BH1417 IC in it.
  2. audioguru2

    Audioguru FM Tx

    Broadcast FM is designed so that the stations boost the treble audio frequencies and FM radios cut the treble down to normal and at the same time cuts down any hiss noise caused by a weak signal. C4 in my circuit does the treble boost. It is a different amount of boost for different countries...
  3. audioguru2

    How to transmit music from PC to music system wirelessly...??

    Hi AN920, In your list of FCC violations: 1) A tow truck company moved and didn't tell the FCC. Their new location caused interference with a competitor's radio system. 2) A TV station was caught with the top red light on their tall antenna burned out. Somebody on one of these forms built my FM...
  4. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Ddav, Welcome to our forum. ;D It is good that you found some high voltage opamps for good reliability.
  5. audioguru2

    How to transmit music from PC to music system wirelessly...??

    I just finished reading reviews about the Ramsey Veronica and The Broadcast Warehouse 1W FM transmitter kits and they do actually produce more than 1W into an antenna. People are making them and using them. I wonder where and wonder if they get caught.
  6. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Egres, My browser displays a square box instead of the "E's" in your name. So I called you Grs before. Your project is very powerful. I think its good voltage regulation will improve with thicker wires. I didn't see the car headlight blowup in your video. 
  7. audioguru2

    How to transmit music from PC to music system wirelessly...??

    I didn't know the BH1417 has flea-powered output. I have never heard of anybody reporting its range.
  8. audioguru2

    Audioguru FM Tx

    Hi Walid, That circuit is nearly the same as mine, except its frequency will drift as the battery voltage runs down because it doesn't have my voltage regulator. It also won't boost treble audio frequencies which are cut in FM radios. The easiest way to increase its range is to use a 9V battery...
  9. audioguru2

    dual switching power supply question

    You have two power supplies in a single case. One of them doesn't produce enough current so you must connect them in parallel but then must add the current readings. Of course the pc will auto start when a single supply is used because it doesn't provide enough current. Get a supply that can...
  10. audioguru2

    How I can make a headphone amplifier

    Hi Jesus, A 741 is a pretty old opamp and is lousy for audio. I don't know if it works with only a single 9V supply. I think it is important to have the volume control ahead of the fixed gain preamp so you can avoid overload. Your schematic shows a positive supply and a negative supply for the...
  11. audioguru2

    Doubling 7805 regulator current is effective?

    Hi AN920, The paralleled regulators will be slightly different. The one with the highest voltage will feed the higher voltage to the lower voltage one. The negative feedback of the lower voltage one will force it to turn off, because the output voltage is too high for it. Maybe your regulators...
  12. audioguru2

    Audioguru FM Tx

    Hi Walid, That RF power transistor has a typical power gain of only 6.6dB at 175MHz in that circuit. Then for 25W output into a 50 ohm antenna its output voltage is 35.4V RMS or 100V p-p, when powered from a 13.5V supply. It needs an input power of 5W at 175MHz. It is used in our Linear FM...
  13. audioguru2

    intercom with less wires

    Each cable would have two pairs (a four-wires cable). Only one cable to each apartment. If the building has multiple floors then install the cables up the shaft where the water pipes and telephone wires go between floors. Then along the hall where the water pipes and telephone wires go to each...
  14. audioguru2

    BIG LED Clock project

    Hi Lancelot, I think he bought and built the kit, instead of cheating the company that makes it.
  15. audioguru2

    Halogen lamp flasher

    Hi Cmer, Use a 555 low frequency oscillator to drive a relay. The relay provides the pulsing 220VAC to the lamp. If you don't like a relay then use a triac or a solid state relay. Hi Lancelot, A halogen light bulb is an incandescent bulb with halogen gas inside. The gas causes the tungsten...
  16. audioguru2

    intercom with less wires

    Hi Mickey, You are planning to make 50 signal decoders when only one is needed. 1) Connect the dialer to a single decoder. 2) The decoder selects which intercom station to call. 3) Reset the system at the end of the call. You are probably going to need cheap two twisted pair cable to each...
  17. audioguru2

    Christmas Pin

    Scrape away the black goop covering its custom-made IC. Then what? Guess that it is a PIC? How are you going to retrieve its program? Never mind its program. Write a program yourself and make it better! Your granny will be tickled pink. ;D
  18. audioguru2

    Christmas Pin

    I couldn't find a datasheet for the CR927 but found one for a CR1025 with the same capacity. It is rated at a current of only 0.064mA. At 400 hours the voltage has gradually dropped to 2.8V then a sharp dropoff after more time. That is the only load shown, for a watch. The average current would...
  19. audioguru2

    Christmas Pin

    The Blinky Lights Company's ad doesn't say how big is its battery nor does it say how long the battery lasts. Didn't you notice? The LEDs blink! Therefore they are turned off for 98% of the time, so the average battery current is low. Each blink in my Chaser projects lasts for only 15ms to...
  20. audioguru2

    Christmas Pin

    No they aren't. They have a range of forward voltage from who knows what (maybe 1.6V?) to 2.2V. You get what they make. If the moon was full when they were made then they might be 1.8V. Look at how dim they are. My normal size LEDs are 100 times brighter. Energizer's CR2016 datasheet shows it...
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