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  1. audioguru2

    Is there a big difference between an FM transmitter and an FM receiver?

    If the transmitter is too close to the radio then the cheap radio overloads and causes static. If the transmitter is too far from the radio then the cheap radio doesn't have enough sensitivity and causes static. Cheap radios don't work very well.
  2. audioguru2

    220 volts Versus 120 volts

    Hi Ante, My electricity is cheap because I don't waste it like many people do. A neighbour pays more than 4 times as much as me. Their incandescent lights are on all the time when I have only one to four compact fluorescent lights turned on only when needed. Their air conditioning is on when a...
  3. audioguru2

    Is there a big difference between an FM transmitter and an FM receiver?

    Hi Bob, Have you tried your transmitter in the house and received on a radio? Is it much better? If it is better then either your car shields the signal too much or the car radio is no good.
  4. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Hana, Does your project work now? Good. Your opamps shouldn't be TL081. Its absolute max total voltage rating is only 36V. If your transformer is only 24VAC which is too low, then the positive supply would be 35.4V and the negative supply is 5.6V. So the total supply for the opamps is 41V if...
  5. audioguru2

    220 volts Versus 120 volts

    Hi Ante, I am paying only about $.10/kWh. Sure it is cheap. It would be a lot cheaper if Canada was smaller because I am subsidizing the people who live hundreds of km from a generating station. Niagara Falls is not far from me.
  6. audioguru2

    Is there a big difference between an FM transmitter and an FM receiver?

    There are cheap lousy ones and there are very good inexpensive ones. Most have a short range to avoid interference to other radios or so they don't break the law of some countries. They are made to transmit from an MP3 player in a car to the car radio in the same car. How far are you...
  7. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Grs, I am not making this power supply project. I think there is a temperature controlled fan project already in our projects section. It uses a lousy low voltage zener diode as its voltage reference that has more temperature sensitivity than its sensing diode. My 96W calculation was with...
  8. audioguru2

    motion sensor

    If you want to detect the motion of people, then a PIR sensor is used to detect the motion of their heat. Look at PIR Sensors in Google.
  9. audioguru2

    How I can make a headphone amplifier

    If you connect a 1M resistor in parallel with the input then the guitar will have a load of slightly less than 10k. Its load should be 1M. If you connect a 1M resistor in series with the 10k input of your preamp then the voltage divider will reduce the level to 1/100th. Your preamp needs to have...
  10. audioguru2

    Audioguru FM Tx

    Hi Walid, His electret mic has a total load of only 762 ohms so it won't have any voltage gain. His preamp transistor has a total load of only 2k ohms so its voltage gain is only 35. The preamp doesn't have any negative feedback so it will be very distorted. The 0.1uF capacitor at the input of...
  11. audioguru2

    How I can make a headphone amplifier

    Hi Jesus, 1) The pickup of a guitar needs a 1M load. The input of your preamp is only 10k. The 741 opamp is old and has poor performance. If a much better TL072 dual audio opamp is used then one opamp of it could be an input buffer with a 1M input that drives the preamp circuit that you have...
  12. audioguru2

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

    The Micromitter FM stereo transmitter circuit is used by many manufacturers of MP3 to car radio converters and they work very well. The Micromitter has an attenuator on its output to reduce its range to be legal in Australia. It is easy to remove the attenuator. Here are some links...
  13. audioguru2

    Service Manuals

    I got the free service manual and lots of chat my TV's problem and about manufacturer's technical bulletins by keying in my Sony TV's model number into Google.
  14. audioguru2

    What RF trancievers will work...?

    I think the receiving antenna should be rigid so it stands vertical. Then your transmitting antenna should also be vertical.
  15. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi GRS, I am glad to hear that you fixed your problem. A regulator makes a lousy transistor, doesn't it? With your 24VAC transformer, the positive supply will be about 32VDC when the project has a 3A load. If the output voltage is set low or is shorted, then the output transistors must...
  16. audioguru2

    Audioguru FM Tx

    Hi Walid, I think that R1 should be 10k so that the jFET in the electret mic gets about 0.5mA and a few volts. I think that the input of the preamp shoud have a total resistance of 30k or more, so the values of the biasing resistors should be high and either have the transistor operate at a...
  17. audioguru2

    Led display Digital Voltmeter question

    If R3 is 12k like Mixos uses then with a 12V input it will show X12.0 but if R3 is 120k then I think it will show 12.00. I think the project's translation wrongly says, "zero volts adjustment" for its trimpot instead of, "calibration adjustment" because the trimpot makes a reference voltage for...
  18. audioguru2

    What RF trancievers will work...?

    Hi CPW, The 2.4GHz module looks good. It won't work the same as an RC system for good models that use a form of pulse width control for motor speed and servo control. So you will need to invent an encoder and decoder yourself.
  19. audioguru2

    What RF trancievers will work...?

    Hi CPW, Does any wireless module manufacturer make anything for 27MHz anymore? They have many on 433MHz and 900MHz. I don't think it is legal to transmit data at 27MHz. Old wireless home phones, radio controlled toys and models and old CB radios use 27MHz. You might need to transmit on 433MHz...
  20. audioguru2

    5 second delay System

    "It is for work, it needs to work if there is no one in the office." It is a riddle. The office has nothing to do with his work so forget about the office that has no one there. The people in the work place like to hear The Rolling Stones with a 5 seconds delay. Lie and tell them there is a 5...
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