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  1. Audioguru

    TDA2030a Amplifier I.C. Specs

    Lower gain requires more negative feedback then the phase shift at high frequencies causes instability and oscillations.
  2. Audioguru

    TDA2030a Amplifier I.C. Specs

    The TDA2030A is also obsolete. Its table 2 has a tiny note that the minimum allowed gain is 24dB. Sure there are fake, defective and used ones sold on ebay.
  3. Audioguru

    TDA2030a Amplifier I.C. Specs

    Maybe ST Micro "assumes" that users know than an audio power amplifier is designed to have very low distortion and a wide frequency response requiring it to have a minimum allowed gain (to avoid instability). Here is what National Semi says about their audio power ICs:
  4. Audioguru

    TDA2030a Amplifier I.C. Specs

    The test circuit in figure 3 has a 13k feedback resistor feeding 680 to ground which is a voltage gain of 1+ (13k/680)= 21.1 which is reduced a little by the non-infinite open-loop gain. Then the voltage gain is about +26dB.
  5. Audioguru

    TDA2030a Amplifier I.C. Specs

    The voltage divider resistor values at pin 2 set the gain but the variable open loop gain might cause the closed-loop gain to be a little more or a little less if "perfect" resistor values are used. The datasheet fails to tell you the minimum allowed gain. Most other power amp ICs that have an...
  6. Audioguru

    A ground / negative connection question

    The grounds in that circuit are common connections of the three at the bottom of the schematic, the connection of the 0.1uF capacitor at pin 4 and pin 8 of the NE555 and the 0V of the 5V power supply. They are all connected together and the letters "GND" to avoid showing wires all over the...
  7. Audioguru

    Powering LED strip

    The tiny A23 12V battery used in a remote control does not produce the high current needed for lighting your 3 LEDs. They will blink for 2 hours slowly dimming. That is a fairly expensive battery to keep replacing.
  8. Audioguru

    Powering LED strip

    Look at the datasheet of your BC547 to see which pin is which. It is different to an Oriental or an American transistor. You probably will not make an LED strip with this extremely simple circuit because an LED strip usually has some LEDs in series. The LED strip can blink if it uses an...
  9. Audioguru

    How can I make Audio Amplifier from 2SK3549-01 MOSFET

    Modern class-D audio power amplifiers use PWM at up to 1.2MHz. Their outputs are push-pull with no DC in the speaker. They use a type of modulation that cancels the carrier to avoid transmitting RF interference without using filters. The Texas Instruments TPA3116D2 stereo amplifier IC produces...
  10. Audioguru

    How can I make Audio Amplifier from 2SK3549-01 MOSFET

    Many people can hear and many speakers produce your 16kHz audio whistle. Nothing is filtering it away.
  11. Audioguru

    Powering LED strip

    You are probably talking about this extremely simple circuit that does not always work. It has the transistor connected backwards so that it has avalanche breakdown causing it to oscillate sometimes and to burn out the LED frequently. A real oscillator always oscillates. You confused everybody...
  12. Audioguru

    How can I make Audio Amplifier from 2SK3549-01 MOSFET

    An audio amplifier produces a voltage output with an extremely low impedance (0.04 ohms or less) and a speaker is designed for it. Then the cone 's momentum is cancelled and the cone does exactly what the signal "says". A speaker has a low frequency resonance that would sound like a bongo drum...
  13. Audioguru

    How can I make Audio Amplifier from 2SK3549-01 MOSFET

    Audio is AC and a speaker works with the AC so its cone can swing back and forth. But your "amplifier" produces variable DC which might cause the speaker cone to be crammed against one side and it can swing only to the middle. Usually your simple circuit would act like a rectifier producing...
  14. Audioguru

    How can I make Audio Amplifier from 2SK3549-01 MOSFET

    Why do you show three transistors in parallel? Why didn't you write the part number of the transistors?
  15. Audioguru

    Powering LED strip

    A circuit to blink the LED on and off is called an oscillator but you described a transistor, resistor and capacitor that turns on and blows up the LED but it never turns off.
  16. Audioguru

    Coronavirus transmission prevention device.

    Today's news said that 44 people have died and hundreds of people were poisoned in Iran by drinking industrial-grade alcohol because a rumor said it would kill the virus. Islamic people are banned from making or drinking booze.
  17. Audioguru

    Coronavirus transmission prevention device.

    Canada has many religions and people of all races. They went to their religious gatherings (China, North Korea, Iran and Italy) and came back with the Corona Virus. A few of them were stupid enough to spread the virus around before seeking medical help. Luckily, not many sick people.
  18. Audioguru

    Coronavirus transmission prevention device.

    Hevans and I are old because we don't smoke. Every day is a Saturday for us to do whatever we want whenever we want. Oh, I quit smoking so long ago that I can't remember when. I also don't drink no more no more.
  19. Audioguru

    Coronavirus transmission prevention device.

    The minister of health in my country said that certain gatherings (he didn't say religious gatherings but news reports did) of people in China, people in Iran and a few other countries at the same time, and people in South Korea spread the virus amongst themselves and all the people that they...
  20. Audioguru

    Mix2052 audio chip

    This is the third website this thread is on. In the first website the battery was 3.7V, in the second website there was a 5.1V power supply used. The datasheet for the amplifier shows very low distortion (0.04% or less) below clipping but it is rated at 6W (Whats, not Watts) with a 5.5V supply...
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