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  1. Audioguru

    Dancing water speakers

    You need the schematic of the Bluetooth circuit to see if its has capacitive-coupled speaker outputs plus grounds for its speakers or if the speakers are each driven by a bridged amplifier. If its speakers are fed with bridged amplifiers then you probably must add coupling capacitors to feed the...
  2. Audioguru

    AM demodulation and DC offset

    While you are talking about an AM detector diode and the DC it produces, did you know that any half-decent AM radio uses the DC to control AGC? AGC is automatic-gain-control so that a weak distant station's audio is almost the same level as a strong local station.
  3. Audioguru

    AM demodulation and DC offset

    You simply use a series coupling capacitor to pass the audio but block the DC. This cannot feed a speaker, it feeds the input of an audio power amplifier that feeds power to the speaker.
  4. Audioguru

    Making a battery to charge my laptop on the road

    Many Instructables are made by little kids who are only 10 years old. The Banggood BMS limits the current way too high at 100A! Also it lets the battery voltage get much too low. Each battery cell is 4.20V when fully charged. Then five in series will feed 21.0V to your laptop. Is that OK? The...
  5. Audioguru

    Making a battery to charge my laptop on the road

    You need a complicated lithium battery charger circuit that is designed and wired so that all your lithium cells are balance-charged. Your laptop has the complicated charger circuit inside it and the laptop "charger" is simply a power supply for it. Your simple idea will probably cause a...
  6. Audioguru

    Questions about LM386 Audio Amplifier.

    Increasing the gain makes it louder only if the sound level is low. The maximum loudness of an LM386 before it reaches clipping distortion is only 0.45W into 8 ohms when powered from 9V which is the loudness of a cheap clock radio. Many modern little Bluetooth amplifiers and radios produce 3W...
  7. Audioguru

    Questions about LM386 Audio Amplifier.

    The schematic from Circuit Basics was drawn by a little kid who never saw the datasheet: 1) C6 is shorted so it does nothing. 2) C7 duplicates C5. 3) R2 ruins the filtering done by C8. The datasheet does not show R2. The schematic from Eleccircuit was also drawn by a little kid who knows...
  8. Audioguru

    2 volt regulator

    It sounds like you did not measure the voltage of a white LED. It is much more than 2V, probably between 2.8V and 3.5V. You said LEDs in plural. If you connect a bunch of white LEDs in parallel then since they all have different voltages, the LED with the lowest voltage will take all the current...
  9. Audioguru

    2 volt regulator

    He made only one post without saying what the 2V is for or how much current he needs. He did not say if an LM317 can be used.
  10. Audioguru

    Speakers clipping w/ TDA7492P

    Common sense shows that your weak little 12V/1A power supply has a max output of 12V x 1V= 12W. The datasheet shows a graph of output power with a little clipping (1% distortion) with the lowest power supply voltage that is 15V and the power in each 8 ohm speaker is 11W for a total of 22W plus...
  11. Audioguru

    2 volt regulator

    I think he is trying to burn out a red LED.
  12. Audioguru

    Ferrite rod antenna explanation

    Thank you. Yes, I am a cool dude.:cool:
  13. Audioguru

    12v Turn signal and running lights?

    The car manufacturer blames blinding daytime running lights on the driver who has a very heavy load (his fat wife?) in the trunk (boot).:)
  14. Audioguru

    12v Turn signal and running lights?

    I have been blinded by Fiat/Chrysler cars and Jeeps that use high beams at full blast as daytime running lights. Now Kia and VW are copying them. High beams shine forward, not downward which lights up hazards on the road. They also trick drivers of those cars that the headlights have turned on...
  15. Audioguru

    Gcse project NEED HELP

    Since the supply is only 3V to 4.5V (three AA batteries) then there will not be any LEDs in series.
  16. Audioguru

    Resistor to limit current to circuit

    A car battery can supply 600A to the starter motor when it and the oil are cold in winter. The clock in the car draws 15mA, not the entire 600A.
  17. Audioguru

    Ferrite rod antenna explanation

    This circuit has more parts than the simple circuit in your first post. It has two RF amplifier transistors (Q3 is like Q2 in your first post) so both invert the signal and the center tapped winding on the loopstick in your first post is not used to invert the signal. It is also a regenerative...
  18. Audioguru

    UM66 is not giving full tone

    The UM66 melody IC is made in India and sold in India. On Google the first few websites talking about it are in India. Most videos about the UM66 are from India except one is from Abdulla Mohammed. The UM66 produces high pitched squeaky buzzer sounds and would never be used in The West as a...
  19. Audioguru

    Ferrite rod antenna explanation

    I have never seen a Mickey Mouse AM regenerative simple radio circuit like this one with the loopstick antenna made into a tuned oscillator. Instead I have seen many normal AM superheterodyne radio circuits that have a loopstick antenna with only a tuned winding and a secondary winding that...
  20. Audioguru

    Ferrite rod antenna explanation

    Can't you see that Q1 is an oscillator? The output of Q1 feeds L3 through the regen control and Q1 is an inverting common emitter circuit.L3 and L2 are a center-tapped transformer that increases the signal level 2 times (the turns ratio) and also inverts the signal and feeds it into the input of...
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