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  1. Audioguru

    Solar panel.

    My friend buys Hobby King Turnigy Li-PO batteries from China and they last for a few flights. I buy Thunder Power American Li-Po batteries and they last for hundreds of flights on my RC airplanes. The ratings of the two batteries are the same. The Chinese people lie about their ratings.
  2. Audioguru

    A radio from 1920 goes to 2017 !

    I think cheap ebay things are poor quality. I do not know what high quality audio products are available or made in France.
  3. Audioguru

    A radio from 1920 goes to 2017 !

    Some people say that ebay Chinese amplifiers and power supplies are designed wrong and produce noises and fairly low power. The datasheet for the TDA7492 IC shows 30W per channel into 8 ohms with fairly low distortion when designed properly and powered from 24V, but it is a stereo amplifier so...
  4. Audioguru

    Wiring together LED lighting for a display

    Then the current is limited by the weak little batteries.
  5. Audioguru

    Calculate how long a battery will feed a project

    The datasheet is a horrible translation from Chinese and does not make sense. It says 12V but shows a maximum of 5.3V and 5.5V. The amount of current used by the LED is not mentioned. It does not say how many LEDs are on the LED strip. It might be a datasheet of one LED IC. You need a datasheet...
  6. Audioguru

    A radio from 1920 goes to 2017 !

    The old radio was designed for AM and shortwave stations that had horrible poor sound quality. Its amplifier and speaker will sound awful. Does it have an auxiliary input for you to connect your phone? Oh, I think you want to use the old radio case but put a modern high quality amplifier and...
  7. Audioguru

    Solar panel.

    My high quality solar panel is made by Coleman. It is 12V, 2.5W and is on sale today in a local store for $7.00US. It comes with many connectors.
  8. Audioguru

    Solar panel.

    "Incorrect rating"! That happens when you buy cheap Chinese junk from ebay.
  9. Audioguru

    555 RC voltage rating

    You have selected audio frequencies. LEDs flickering at these frequencies will look the same as LEDs that are continuously powered by DC. You cannot see a frequency that is 24Hz or higher which is why a movie flickers at 24 frames per second. The lights in your home flicker at 120Hz. Do you...
  10. Audioguru

    A radio from 1920 goes to 2017 !

    Is it a muffled-sounding AM radio that plays lots of AM static sounds? Will it pickup and play a few stations at the same time?
  11. Audioguru

    555 RC voltage rating

    A CD4060 counter IC has an oscillator and 14 stages to give up to 14 octaves of squarewaves outputs.
  12. Audioguru

    Audio voiceover on TV

    I did not know that blind people "watch" TV with a voice telling what is happening. Deaf people watch TV and read the captioning words.
  13. Audioguru

    multiplexing a 3A per channel led grid

    LEDs have a maximum allowed continuous current rating and a peak current rating that is much higher. You can increase the current in the multiplex pulses so the brightness is almost like continuous.
  14. Audioguru

    Guitar Amp Modification

    An ordinary single-ended amplifier powered from 12V produces an output of about 1.5W into 8 ohms at fairly low distortion. If the volume is turned up too high then the horribly distorted squarewaves produce 3W. The cheap little 2W speaker was doomed. A 3" or 4" cheap little speaker is used in a...
  15. Audioguru

    AC current help

    You Tube has videos of Levitation Using Eddy Current.
  16. Audioguru

    How to build a ultra high frequency speaker for bats

    Some cheap tweeters are advertised to deliver ultrasonic power but they have no spec's and probably do not produce ultrasonic sounds, just a little heat instead. The piezo transducers probably produce only a narrow range of frequencies near resonance. Bats will think it is a truck backing up...
  17. Audioguru

    Help finding the right battery

    Like this cheap Chinese battery (and many more) from ebay:
  18. Audioguru

    Solar panel.

    A DC motor that starts running is stalled. Look at its spec's, its stalled current is much higher than its current when running with no load. Maybe your meter is too slow to show its stalled current then shows its current when it is running up to speed. My solar panel is 12V with its rated...
  19. Audioguru

    555 RC voltage rating

    Sure a transformer steps up the power. If the output of the 555 is 10V peak and the load is 1k then the power is 0.1W peak. The output of the 555 is 10mA peak. If the transformer steps up the voltage to 31.6V peak then the power in the 1k ohms load is 1W and the current in the 555 output is...
  20. Audioguru

    Amplifier DC Power Supply Problem

    ALL audio amplifiers have plenty of negative feedback because it "reduces the voltage gain to a useable amount, reduces distortion a lot, increases the bandwidth and reduces the damping factor a lot." 60W RMS into 8 ohms has a peak voltage of 31V which causes a peak current of 3.9A. Your...
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