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  1. Audioguru

    Coronavirus transmission prevention device.

    I saw antivaxxers making a protest about mandates blocking them. They had signs lying about the vaccines and telling people not to get the "poisonous" vaccination. None of them were educated or were doctors.
  2. Audioguru

    Coronavirus transmission prevention device.

    In some countries, you pay for your hospital care and funeral. Here in Canada taxpayers pay for it. Therefore we had mandates to block antivaxxers. Their "rights" are ridiculous and they should live on another planet with others like them. Masks are not perfect so they only reduce the spread of...
  3. Audioguru

    Coronavirus transmission prevention device.

    Almost all well educated people and doctors agree with you.
  4. Audioguru

    Coronavirus transmission prevention device.

    Antivax people are here too? Here is the truth:
  5. Audioguru

    Coronavirus transmission prevention device.

    To show the effectiveness of the Covid-19 vaccines, look at countries where few people are vaccinated and compare with countries that have nearly everybody vaccinated. A huge difference in the numbers of cases, hospitalizations and deaths. New variants of the virus are developed in unvaccinated...
  6. Audioguru

    TSOP and 555-timer circuit to turn on LED with IR remote control

    The video has no parts list (which of the many TSOP ICs is used or which one is available in India?). It also has no schematic. It will probably work with a TSOP1738 (look at its datasheet) and there are many circuits on the web that explain about an LM555 used as a set-reset latch. Do you know...
  7. Audioguru

    BJT AC Analysis - feedback pair equivalent circuit

    Also look in Google for Sziklai Pair.
  8. Audioguru

    Comparison of two operational amplifiers in relation to the load

    The resistance of your 1 ohms load on either opamp is a dead short. Most opamps need at least 100 ohms to drive the 100nF capacitor. Maybe the 100nF capacitor is actually only 100pF of stray wiring capacitance.
  9. Audioguru

    Weird issue TDA7377 amplifier

    I hijacked the original muting problem because nobody explained how adding a missing capacitor to ground fixed the DC muting. The amplifier output power was low due to the low supply voltage and speakers being a home's 8 ohms instead of a car's 4 ohms. The Taiwan amplifier IC that had the...
  10. Audioguru

    Weird issue TDA7377 amplifier

    The heatsink should be on the open on the end of the circuit board with hot air rising from it and cool air from below replacing the air. The circuit board blocks air motion.
  11. Audioguru

    Weird issue TDA7377 amplifier

    With a 12V supply and two 8 ohm speakers then the power output and heating are not much unless you play continuous tones instead of music. Maybe the Asian design causes the amplifier to continuously oscillate at a very high frequency that will overheat it.
  12. Audioguru

    Weird issue TDA7377 amplifier

    The TDA7377 amplifier IC was designed a number of years ago by a company in Taiwan. I do not know if ST Micro bought the design. Modern European and American audio amplifier ICs are class-D for high efficiency and fairly low heating.
  13. Audioguru

    Weird issue TDA7377 amplifier

    You show the datasheet schematic for stereo plus bridged subwoofer. Then the single-ended stereo outputs produce only 3.7W each into 8 ohms with low distortion when the supply is only 12V. Also, the single-ended outputs are out-of-phase with each other.
  14. Audioguru

    Weird issue TDA7377 amplifier

    If your speakers are 8 ohms then the power is halfed.
  15. Audioguru

    Weird issue TDA7377 amplifier

    They lie about the output power. They use a 14.4V power supply and say 30 fake Watts or 20 severely distorted Watts. 40 real Watts in to 4 ohms is an output of 12.65V RMS into 4 ohms. 12.65V RMS is 17.89V peak and is 35.77V peak-to-peak. The amplifier channels are bridged so each speaker wire...
  16. Audioguru

    AC Power wiring to Light Bulb

    Are incandescent light bulbs made and sold anymore?
  17. Audioguru

    4.5 volt to 12volt

    You do not use a current meter to short-circuit a supply. Instead you connect the current meter in series with the supply, the current-limiting resistor and the load. If you are measuring the current of the 20 LEDs and the reading is 0.7A then each of the 20 LEDs is drawing 0.7A/20= 35mA which...
  18. Audioguru

    4.5 volt to 12volt

    The LEDs appear to produce white light (a bit yellow) then their voltage cannot be less than about 3V and they are probably 3.2V. With 4.5V of new battery cells the 20 ohm resistor will have a current in it of (4.5V - 3V)/20 ohms= 75mA. The resistor heats with 75mA squared x 20 ohms= 0.11W. Each...
  19. Audioguru

    4.5 volt to 12volt

    A cheap battery cannot produce a high current. The "Super Heavy Duty" AA cells from ebay are mostly full of rice. An expensive Name-Brand battery produces enough current to explode LEDs that do not have something to limit the current. Oh, maybe your 3V battery is a little CR2032 coin cell that...
  20. Audioguru

    4.5 volt to 12volt

    570 ohms is not a standard resistance. LEDs must have a resistor or circuit in series to limit the current. Without the resistor then an LED will burn out immediately when a voltage too high is connected to it. The white LEDs use about 3V and three new batteries produce 4.5V. Then the voltage is...
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