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  1. Audioguru

    Fan speed control

    There is a HUGE difference between what is shown on the datasheet and what you said you did:
  2. Audioguru

    Portable Amp

    Are you talking about using discrete inductors and capacitors (choke method) for a crossover network connected to the woofer and tweeter speakers and want a comparison of using IC active filters driving separate amplifiers (IC method)? Then active filters and separate amplifiers sound better...
  3. Audioguru

    Fan speed control

    A capacitor from input to output on the LM317 is WRONG! A capacitor from input to the ADJ pin is also WRONG! The heating in the LM317 is the voltage across it times the current through it. The voltage is 37V - 14V= 23V and I have never seen a fan that draws less than 100mA so the LM317 chip...
  4. Audioguru

    Transistor Question

    The motor uses a certain amount of current and the transistor must be able to pass that current. But you did not say how much current the motor uses. The motor current is the highest when it starts running because that is when it is stalled. If you tell us its stalled current when it is powered...
  5. Audioguru

    Optical Pickup

    It won't work. The IR beam is much wider than a guitar string. Then shadow of the vibrating string will not change the amount of light so the output of the IR detector will not have a signal of the vibration. If the IR beam is the same width or wider than the guitar string then the output will...
  6. Audioguru

    Portable Amp

    The videos have extreme distortion. I guess they like it like that.
  7. Audioguru

    can IR sensor be changed?

    One device says its modulating frequency is 38kHz, not a channel number. The other device says its remote has a channel number, not the modulating frequency. Apples and oranges are not the same. The manufacturers never thought that two or more remote devices will interfere with each other.
  8. Audioguru

    Portable Amp

    A crossover filter does not boost anything. It is a lowpass circuit for the woofer and a highpass circuit for the tweeter. At the frequency where they cutoff their levels are half power so combined they produce no boost and no loss.
  9. Audioguru

    AAA Battery charger

    You found a very old circuit made to charge ancient obsolete battery cells. It has nothing to adjust the charging voltage and current. Since the LM317 and resistors have minimum and maximum values then this charger circuit could have a low voltage of 1.3V at low current of a high voltage of 1.8V...
  10. Audioguru

    Dc booster to step down

    It is silly to step down the solar panel voltage that is too high to 1V-4V that is lower than you need then boost it back up to 5V.
  11. Audioguru

    AAA Battery charger

    Are rechargeable alkaline batteries made anymore? I saw them 30 years ago and they were almost useless. Ni-Cad rechargeable batteries were also used about 30 years ago. Today Ni-MH and Lithium rechargeable batteries are used and a charger that charges, detects a full charge then then shuts off...
  12. Audioguru

    Dc booster to step down

    He also said he wanted "To dc step down current", not to step down the voltage. I have never seen a "mobile charger" that works from a voltage as low as "1 to 4v", they all use 5V.
  13. Audioguru

    (Russian) 1978 Radio's audio signal path from cassette deck

    I cannot see the tape playback head on the schematics. The voltage gain of the power amplifier is extremely high (15k/56 ohms= 268 times) so maybe the radio parts are attenuated and the tape playback head feeds through EQ resistors and capacitors that might be faulty. Maybe the tape playback...
  14. Audioguru

    can IR sensor be changed?

    Nobody knows the IR modulation frequency of the cheap Chinese striplights. It might be the same 38kHz frequency as the cheap Chinese IR emitter and receiver. Nobody know if the cheap Chinese IR emitter and receiver will fit and work in the striplights product.
  15. Audioguru

    Dc booster to step down

    You show a buck voltage converter that steps down the voltage and uses an IC to make Pulse-Width-Modulation and an inductor. If you make a boost voltage converter then it will step down the current.
  16. Audioguru

    Portable Amp

    Loudness is produced by how many Watts an amplifier can produce into a speaker that is near you. If the speaker is far from you then it will not be loud unless the Watts is increased. The number of output Watts must be with a rated percentage of distortion number. 0.1% distortion or less cannot...
  17. Audioguru

    Forward and Reverse on Low Volt DC motor using solid state electronics.

    Your Mosfet has a maximum on-resistance of 5.5 ohms when its input is 10V so with 1A though it its voltage loss will be 5.5V so the load gets only 1.5V and the tiny Mosfet melts with 5.5V x 1A= 5.5W of heat. Your Mosfet is rated at a very high 400V so its on-resistance is high. The IRLZ44 is...
  18. Audioguru

    Building a comparator

    The Digikey article talks about charging a single Li-ion cell, not a balanced charger for charging more than one cell.
  19. Audioguru

    Woo-Woo Small Generator Homemade, Created In Educational Purpose Lighting E 27 230 V Led Bulb

    The light bulbs are not bright enough, low power is going to them. Whatever is out of balance, vibrating and making all that noise is probably reducing the efficiency. If my mini drone made that much noise then it would not have enough power to fly. Your generator produces a frequency much...
  20. Audioguru

    Circuit Which Turn On The Light As A Response To A Specific Sound Sequence ?

    I think your beep, beep detector will also detect my dog (bark, bark) and my wife (DINner's REAdy). My daughter bought a keys finder and hand-clap switch that activated so often that their batteries lasted only for a few days.
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