Can you please analyze a bjt sound amplifier with a ZTX123 trans.??or help me analyze it myself??THANKS?
368420
Yes, I may be able to help.\n\nGet in touch by private message in the first instance.
878170
Let us remember what is dB. It is the logarithm of relaton, at which 10dB = 1B = Lg(I/Io)=1 when I = 10 Io, That is when we enhance intensity 10 times, we get 10 dB more, when we enhance intensity 100 times, we get 20 dB more, and when we enhance intensity 10000 times, we get 40 dB more.\n\nIn acoustics, it is usually accepted to take the Io as the intensity at threshhold sound preddure of 20 microPascal. \n\nEarnestly speaking, I do not remember what is 120, though I belive this is the deciBell Intensity of 1Watt/sq.m. \n\nBut you do not need this figure at all to solve the problem. You only need two figures for sound meter figures and one for the first distance to find the second distance.\n\nAt the initial distance from the center of loudspeakers Ri of 2.8 meters you have intensity Ii of 130 dB, and the total sound power would be W = 4PiRi^2Ii , the same power will be at the second distance (we assume that the sound power is not dissipated in air significantly). So, at distance Rx (this is the distance which we shall have to determine), the power W = 4PiRx^2Ix = 4PiRi^2Ii.\nSo, the relation Ii/Ix = Rx^2/Ri^2.\n\nLet us now take into accont that\n 10 lg(Ii/Ix) = Bi - Bx = 130 - 90 = 40 dB\n from this      lg(Ii/Ix) = 4,\nand from this     Ii = 10000 Ix.\n\nThat is, the intensity at 90 dB is 10000 times less than at 130 dB.\nAnd from here, \nRx^2 = 10000Ri^2,\nhence  Rx = 100 Ri = 280m\nAnd this is the answer
904869
amplification by billion volts!
351695
It'll sound fine...but another cab isn't gonna make that much of a difference for you, aside from range of sound and loudness, basically.  It's really all about the amp head.  If you have a good distortion, you'll get the sound you want though.\n\nGetting the Marshall head is a good idea though.  Go for a tube.  Spend the extra money.  It's worth it.
252364
I had the same thing happen.  It was the wiring in my speaker cord.  You might need new speakers.
219925
Look at it this way. When you configure an amplifier as a common emitter, the emitter goes to ground. When a signal enters the base, it increases the emitter current. This causes a corresponding increase in the collector current. This makes the collector resistor drop _more_ voltage, producing less voltage in the load.\n\nSo consider the extreme cases. If no signal is present on the base, the transistor is effectively "off" and all the voltage at the collector resistor is avaialble to the load.\n\nThe other extreme case is if so much signal is at the base, the transistor saturates "on" -- then the collector will be at, say, 0.2V or so and the collector resistor will drop almost all the voltage, leaving nothing for the load.\n\nSo you can see that a lot of signal produces a little voltage, and no (or a little) signal produces a lot of voltage. Phase inversion!
159857
this si not a physics question. this is a basic IC that perhaps still and certainly at one time was available at radio shack. the ic 741 behaves as ANY op amp and it is electronics 101.......happy homeworking.
705960
check the cable and try new speakers or call the manufactures
96289
check cables, check overall volume on pc, and for creative labs for example there is a sound mixer with volume labels for different types of inputs\n\nStill not working?  Check for switch on speakers, are they plugged in\n\nStill not working? Bring up control panel -> sounds -> check mute button, check volume, click on a sound  like asterisk, hit play still no sound?\n\nFind a geek...
817282
you might just have a defected input... if it is terrible quality sound on a new PC then i suggest calling customer service.
656178
on the back of the amplifier there should be some 'snap connectors' which the bare wires from the speakers go in to. the 'snap connectors are usually black and red.
456589
Disconnect/turn down the sub woofer, \nor use a smaller speaker\nor connect the output to a stereo and use the equalizer to turn it right
273942
It is assumed you have completed all of the tutorials on basic electronics because without that basic grounding you will go nowhere here. It is assumed you have a good understanding of ohms law to be able to follow the necessary calculations here.\n\nMany people are interested in Audio Amplifier design. If this is your area of interest then the first thing I sincerely recommend you do is buy this excellent reference book through my amazon affliate program.\n\nHigh-Power Audio Amplifier Construction Manual - G. Randy Slone, Randy Slone - highly recommended. Paperback and 476 pages.\n\n"Design and build awesome audio amps. Amateur and professional audiophiles alike can now design and construct superior quality amplifiers at a fraction of comparable retail prices with step-by-step instruction from the High-Power Audio Amplifier Construction Manual. Randy Slone, professional audio writer and electronics supply marketer, delivers the nuts-and-bolts know-how you need to optimize performance for any audio system--from home entertainment to musical instrument to sound stage".\n\n"Build a few simple projects or delve into the physics of audio amplifier operation and design. This easy to understand guide walks you through: Building the optimum audio power supply; Audio amplifier power supplies and construction: Amplifier and loudspeaker protection methods; Stability, distortion, and performance; Audio amplifier cookbook designs; Construction techniques; Diagnostic equipment and testing procedures; Output stage configurations, classes, and device types; Crossover distortion physics; Mirror-image input stage topologies".
1131296
I'm assuming you're doing computer audio out TO some sort of sound system: eg. cord is going from computer to speakers.\n\nThere are 3 possible sources of noise:\n\n1.  Your sound card sucks and is not shielded.  This is unlikely unless you spent less than $10 on it.\n\n2.  The speakers themselves have poor electronics.  My guess is that since you called it an 'audio receiver' you're savvy enough to not have crappy speakers.\n\n3.  The cables themselves.  This is the most common source of noise in audio systems.  If you get poor quality or non-shielded cables, you'll get noise on the line from ambient electromagnetic radiation.  Make sure you get really good cables, because they are often the weakest link in ANY electronics system.\n\nMonster makes good cables, but so do other companies and Monster tends to be a little over priced.  You can tell a good cable by how heavy it is though, and how flexible it is - poor quality cables will feel light and be very, very floppy, whereas high quality cables will feel heavier, thicker, and won't flex quite as much due to the thicker shielding.
436468
More info is needed. \n\nWhat is the pass band frequency, what is the spectral content of the input signal. Ideally how steep do you want it?
746361
Paul's quite right -3.01(something) dB is half the power. It's based on the Bel (after Alexander Graham ) which is log10(some power / some other power) but is a bit of a big change (3 Bel is a factor of 1000) so people use the decibel (dB) which is 10*log10(P2/P1)\n30 dB =1000  -30 dB = 1/1000\n\nIn terms of your low pass filter, if P2 is the output power you get if you put a clean narrowband signal of power P1 and center frequency w into your filter then when 10*log10(P2/P1)~=-3,  w is your 3dB frequency.  \n\n\nGood luck
20056
Check the D-sub cable loosened or not.\nLCD set up the wrong source state.