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  1. Audioguru

    12v bar graph help

    The outputs of the LM3914 will saturate with a voltage drop of only about 0.7V if the LEDs have built-in resistors and the output current of the LM3914 is set for their current or more but do not exceed 25mA. Does your throttle position sensor output go as high as 11.5V? Why doesn't it have a...
  2. Audioguru

    12v bar graph help

    A voltmeter circuit using an LM3914 is very simple. Two resistors set its input voltage range and set the LED current.
  3. Audioguru

    ASHTON BSK-158 BUSKING AMP

    It is a powered speaker from Australia. Its output is 15W RMS into its 8" speaker. Its battery is 12V but its owners manual does not say its chemistry. It is probably a little lead-acid battery and the amplifier is probably a bridged car radio IC. The speaker is probably 4 ohms. Why don't you...
  4. Audioguru

    Outdoor Motion chasing led light strips

    I have never seen an LED strip with the LEDs chasing but I have made many chasers myself. If only one or a few LEDs are turned on at a time then the strip is fairly dim. Maybe the controller can light most of the LEDs and make a running turned off LED or a few of them.
  5. Audioguru

    Outdoor Motion chasing led light strips

    Some LED strips have an IC for each RGB LED then a digital controller can address each LED individually.
  6. Audioguru

    Lithium Ion 18650 cell capacity

    2.5V is too low to discharge a cobalt-Lithium-ion cell. It makes their capacity rating higher and you will be replacing the over-discharged cell soon.
  7. Audioguru

    LED Circuit

    The datasheet from Energizer or Duracell shows that an A23 12V battery is a very weak little thing. It is designed to supply a current of only 0.5mA for a few days or much less current for weeks. You shorted it with your LEDs so now it is dead. An LED must have a series resistor to limit its...
  8. Audioguru

    Lithium Ion 18650 cell capacity

    Here is a "good" Li-Ion battery for you:
  9. Audioguru

    Lithium Ion 18650 cell capacity

    Discharging an ordinary Li-Ion cell (Panasonic's might be different) to as low as 2.5V will destroy it. When the voltage of the Lithium batteries in my RC model airplanes drop to 3.0V then the motor pulses as a warning. The manual says that repeated flying to this low voltage will damage the...
  10. Audioguru

    Lithium Ion 18650 cell capacity

    The 19200mAh number might be the typical, some are better and some are worse since they are all not exactly the same. I agree that the cutoff voltage and charging voltage make differences.
  11. Audioguru

    What will be the output signal of op-amp?

    The OP says that his input is applied to the inverting input but it is shown applied to the non-inverting input! Another problem is that his inverting output is not indicated.
  12. Audioguru

    Solar panels with 100W led

    If you try to test the maximum current from the solar panel in direct sunlight then the multimeter is a dead short circuit and the current will be much higher than the maximum allowed current. The datasheet for the solar panel will show its voltage drop and its current increase with lower load...
  13. Audioguru

    Solar panels with 100W led

    The solar panel has a maximum allowed rating 5W at 12V. Then its maximum allowed current is 5W/12V= 0.417A. It looks like you are not limiting the current to no more than 0.417A then either the LED or the solar panel (or both) will soon burn out. Of course a solar panel is used in direct sunlight.
  14. Audioguru

    Amplificator Audio, with LM741

    The LM741 opamp was introduced 49 years ago and was never planned for audio because it has a high noise level, distortion and cannot produce high level frequencies above only 9kHz. Its datasheet only shows a +/- 15V supply so many of them do not work if the supply is 10V or less. Use a modern...
  15. Audioguru

    What will be the output signal of op-amp?

    I explained why his circuit did not work and I showed all the details on my schematic that works perfectly.
  16. Audioguru

    What will be the output signal of op-amp?

    Your opamp has no power supply. Its inputs have no biasing. It has no negative feedback. It has an extra output (opamps have only one output). Some audio power amplifiers have a differential outputs (two outputs) and some have built-in biasing and negative feedback. Here are two opamp circuits...
  17. Audioguru

    Alternative Transistors for LM317 High Current Voltage Regulator Circuit

    He wants only 5A, not 45A. A single power transistor will be fine for only 5A.
  18. Audioguru

    Can you check over this Circuit?

    If you can't fix this simple circuit then I guess you are simply learning how to solder parts together, or use a solderless breadboard. I fixed it (but I didn't make it and test it) but your teacher should have taught you how to fix it.
  19. Audioguru

    Speakers clipping w/ TDA7492P

    Only a moron would turn up the volume too high. It is normal for an amplifier to have "too much gain" so that faint sounds can be made loud enough. You said, "so no one can turn the volume so high that the speakers start clipping" which is wrong because normal people will hear clipping and...
  20. Audioguru

    Speakers clipping w/ TDA7492P

    How did they make that Chinese amplifier so cheap? 1) The heatsink is too small. 2) High current traces have copper too thin and narrow. 3) Not enough filtering. You used a 19V/2A power supply and played both (?) 4 ohm speakers at maximum power when distortion was pretty high. The graph in the...
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