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  1. Audioguru

    Powering 0402 smd LEDs

    My eyes are 75 years old and about 10 years ago I was completely blinded with cataracts. So an eye doctor removed the cloudy lenses inside my eyes and put in new synthetic lenses to make my vision better than new. I could see perfectly the day after the fix. Almost the same thing about my heart...
  2. Audioguru

    Powering 0402 smd LEDs

    Two series CR2032 batteries will last about 1.5 times longer than two series CR2025 batteries. Use Name-Brand batteries, not the cheeep junk sold in The Dollar Store.
  3. Audioguru

    Powering 0402 smd LEDs

    The battery cells are so small that if a few LEDs are turned on together then you will see them dimming as the battery cells quickly die. They are designed for much less current than your LEDs will use, unless the LEDs are very dim. A dim little tea light uses a much thicker CD2032 battery cell...
  4. Audioguru

    Powering 0402 smd LEDs

    Your vision sees green light as being brighter than other colors. The datasheets for LEDs show that each color has its own forward voltage. The datasheets for LEDs shows that some are focused into a bright narrow angle beam (spotlight) and others appear not as bright but over a wide angle...
  5. Audioguru

    Powering 0402 smd LEDs

    If the 2-cells battery is 6V with a 50 ohm internal resistance when new, a 150 ohm resistor in series with a 2.0V red LED results in a current of (6V - 2V)/50 ohms + 150 ohms= 20mA which is very bright and the battery will die soon. Is that what you want?
  6. Audioguru

    Powering 0402 smd LEDs

    Nobody makes a CR3025 battery cell. Do you have CR2025 battery cells instead? The Energizer datasheet for a CR2025 battery cells says its voltage is 3.0V when new with no load and is 2.9V with a load of only 0.186mA. It is a small coin cell so it has 25 ohms to 100 ohms of resistance in it...
  7. Audioguru

    White noise

    Audio noise can be white or pink. It has random frequencies and random amplitudes. White noise has constant amplitude peaks vs frequency and sounds like mostly high frequencies. Pink noise has equal power in each octave (white noise with a -3dB per octave lowpass filter) and sounds like it has...
  8. Audioguru

    How to connect piezo speakers to an amplifier

    Tweeters are designed to produce audio that has only occasional full power bursts. You will probably burn out the tweeters by driving them with a full power tone continuously. The same for an amplifier. A tweeter uses a capacitor as a crossover to block low frequency sounds that will destroy...
  9. Audioguru

    How to connect piezo speakers to an amplifier

    +10dB needs 10 times the amplifier power and sounds twice as loud. +3dB is double the amplifier power and sounds only a little louder. Adding +15dB will cause an explosion. Amazon sells cheap junk made by a company that nobody knows about. The Amazon tweeter has Absolutely No Detailed Audio...
  10. Audioguru

    How to connect piezo speakers to an amplifier

    The piezo tweeter and the sound level meter are VERY cheap with poor quality. I think maybe your amplifier or even maybe your ears are clipping and producing a frequency of may half or 1/3rd the 17.5kHz you are playing. The sound level is extremely high.
  11. Audioguru

    Creating 1.12v ac at 22.5khz

    AliExpress sells a new version of this circuit but they do not ay much about it.
  12. Audioguru

    Creating 1.12v ac at 22.5khz

    You show the circuit (4 pins IC) from a cheap low power solar garden light that takes the 1.2V from a single Ni-MH battery cell and steps it up to a few volts with the inductor (it looks like a resistor) and Schottky diode at 250kHz to 500kHz. Then the diode and capacitor on the right side...
  13. Audioguru

    Creating 1.12v ac at 22.5khz

    LEDs do not work from 1.12VAC at 22.5kHz. Also, LEDs do not create 1.12VAC at 22.5kHz. If the LEDs are blue or white and are in series then you need to power them from about 320VDC at about 10mA. The color of an LED tells you what voltage it needs. The size of an LED and how bright you want it...
  14. Audioguru

    Speakers in series - capacitor

    Your high voltage battery will be too big and heavy to be portable. 22.2V is six series 3.7V lithium cells that produce 4.2V each when fully charged then the total is 25.2V for each battery. Why bother stepping them up to 26.4V? You will need 24 18650 Lithium battery cells for the amplifier to...
  15. Audioguru

    Speakers in series - capacitor

    Why do you use four 2 ohm tweeters in series instead of one 8 ohm tweeter? To make the sounds go left, right, front and back?
  16. Audioguru

    Transistor radio repair - Philips RR-230

    The radio looks very very old so i think it has an output transformer. I think you are measuring the normal resistance of the output transformer. Disconnect the speaker then measure only the speaker.
  17. Audioguru

    Transistor radio repair - Philips RR-230

    The sound is extremely distorted even when you turned down the volume and it also sounds tinny because the low frequencies are missing. Listening to it I realize that in my life and my job as a sound systems engineer I have NEVER listened to an amplifier clipping. I do not think your amplifier...
  18. Audioguru

    Transistor radio repair - Philips RR-230

    Your Google Drive is not an ordinary audio player so I could not hear your distortion. In Google I entered, "audio example of amplifier clipping" and got a few video explanations and demos of ampflier clipping. The parts in a cheap old radio are obvious. A 'scope will show clipping at the...
  19. Audioguru

    Transistor radio repair - Philips RR-230

    Any radio produces distortion above a certain output power. The radio is designed so that normal levels have the volume control set a little above halfway so that low level inputs can be turned up. But then normal input levels can be turned up too high where the output cannot go that high and...
  20. Audioguru

    I cant measure voltage on 100 picofarad capacitors on multimeter

    The input resistance of a multimeter is 20 million ohms. Adding 1k will make a VERY small difference of 0.005%. The discharge time of 2 thousands of a second is too small for a multimeter to measure the voltage. Also your vision will not be able to see the numbers.
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