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  1. Audioguru

    Transistor chains

    I did not say that the person (the OP) asking the questions designed that horrible wrong circuit, I am implying that horrible circuits appear all over the web, especially from the website where that one came from. I showed how to fix that circuit.
  2. Audioguru

    Transistor chains

    The new circuit is poorly designed (by a monkey or a dog?) therefore it is not sensitive. LDRs have a wide range of sensitivity because some are huge and others are small. I have two small LDRs and the most sensitive one measures 9k ohms when near a window on a cloudy day. I redesigned the...
  3. Audioguru

    Transistor chains

    Of course the LED is brighter in your new circuit, it is missing an important current-limiting resistor in series with it. The 2N3904 has a current gain of about 100 times. The 1k base resistor can have a voltage drop of 0.5V then its current is 0.5V/1k= 0.5mA and the emitter current (and LED...
  4. Audioguru

    Transistor chains

    The first transistor is an emitter-follower (look it up). It amplifies the low current output from the photo resistor when the light is not bright. So it makes the circuit more sensitive. The second transistor will work fine without the first transistor when the light is bright.
  5. Audioguru

    Can it damage IC if connecting two speaker in parallel in output?

    The amplifier IC does not need a voltage regulator. The amplifier is designed for an 8 ohm speaker for each channel. With 2.6 ohms (8 ohms // 4 ohms) or 2 ohms (two 4 ohms in parallel) either the amplifier will be destroyed by the current that is too high or the amplifier will limit the current...
  6. Audioguru

    What can be happen if I use 10 inch 8-ohms speaker instead of 8 inch 8- ohms?

    A loudspeaker made by a quality company has a detailed datasheet showing its sensitivity, frequency response and all the Thiel/Small specs for you to design its enclosure. Usually the datasheet shows an enclosure design. If your "local market" sells speakers without any detailed specs then you...
  7. Audioguru

    Strange node Notation (clear circle)

    Are the numbers the pin numbers on the IC?
  8. Audioguru

    Speaker

    The Vizio Sound Bar/Stand is basically a center speaker. It probably has stereo mids/highs speakers but they are too close together to produce stereo. The Sound Bar/Stand has a built-in little woofer to produce mid-bass bit it is too small to produce deep bass. Their website does not give...
  9. Audioguru

    Battery Chemistry

    When I was young my friends and I did not make batteries, instead we made rockets and very powerful fuel for them. They all blew up! Luckily none of us were injured.
  10. Audioguru

    Should I be able to use this battery with these LED's?

    Before we talked about a lithium 4 cells battery that is 12.8V when it should be disconnected and is 16.8V when fully charged which is too high for the 12V LEDs strips with a maximum allowed voltage of 14.8V. The Airsolt battery might have 3 Lithium cells which is 9.6V to 12.6V. Of course the...
  11. Audioguru

    Battery Chemistry

    It sounds like you are making an old Carbon Zinc battery. They are not made here anymore but leaky "heavy duty" carbon zinc batteries are made in China. Ordinary disposable batteries here are alkaline type that are much better than the old carbon zinc type.
  12. Audioguru

    Should I be able to use this battery with these LED's?

    All products that use a rechargeable Lithium battery have a low voltage detect and disconnect circuit. You could use a comparator and voltage reference (an LM10 IC has both) and the circuit must disconnect them also so they don't continue to run down the battery voltage. Maybe ebay has a circuit.
  13. Audioguru

    Need with homemade inverter with tl494

    6000W is a lot of power. What is the size of the neighbourhood that uses all that power? Output current is caused by the resistance of the load. Lower resistance causes higher current. Output voltage drop occurs when the circuit is so simple that it is missing negative feedback and is caused by...
  14. Audioguru

    Need with homemade inverter with tl494

    20A at 300V is 6000W (!). The circuit might have a good efficiency of 80% so the low voltage side must produce 7500W (!).Then the poor little Mosfets must conduct 7500W/12V= 625A (!). Impossible. Even an output of only 3A at 300V (900W) might be impossible for that simple circuit because the...
  15. Audioguru

    LED lamp isnt working, but want to try fix it!

    The LEDs are all connected in parallel (horrors) so the little battery is probably a single cell Li-Po. The battery is ruined if it has been fully charged for months or has been discharged too low. The "charger" circuit appears to be too simple and will overcharge a Li-Po battery cell which...
  16. Audioguru

    Help With Circuit

    Your first schematic has the load connected to -5V so the output voltage is positive-going. It needs a P-channel Mosfet. The last schematic has the load connected to ground and a negative-going output voltage impossibly comes from magic. You could connect the load to +5V and use an N-channel...
  17. Audioguru

    Help With Circuit

    Because the drain and source are swapped. My "corrected" copy fixed it.
  18. Audioguru

    Help With Circuit

    Your new circuit is completely wrong. 1) A current source does not have a resistor in series with its output. Yours has 1 Megohm. 2) The (-) input of the opamp cannot be -0.5V unless the load voltage is +450.5V. 3) You have the output resistor connected to the source of the Mosfet but instead...
  19. Audioguru

    Help With Circuit

    I see that you do not show an N-channel Mosfet in your schematic, It is an upside down P-channel. Schematics should always show a part number.
  20. Audioguru

    Help With Circuit

    A current source uses negative feedback. Your circuit has positive feedback.
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