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  1. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    0.1μF feeding 500k ohms has a cutoff frequency (-3dB) calculated to be extremely low at 3.2Hz. We cannot hear below 20Hz and many speakers cannot produce frequencies below 35Hz. I do not know the inductance values you have. 470pF might not be a good value for them. Look in Google for an LC...
  2. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    The IF for an FM radio is 10.7MHz but your simulation has a generator frequency of 5.1MHz. It is easy to calculate the inductance and capacitance for an LC to resonate at a selected frequency. The discriminator circuit you posted has a low power Jfet with a fairly high output impedance trying...
  3. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    Michael, it looks like you are trying to simulate a circuit, not build the circuit. You make many errors when you copy a schematic. Here are my attachments: 1) This discriminator from the book has no strong DC bias on the diodes like your circuit has. 2) Your ratio detector is completely...
  4. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    It looks like you copied the Foster Seeley discriminator wrong:
  5. Audioguru

    Car radio static

    A cheap or defective FM radio picks up AM static. A good FM radio does not. You never said if the static is heard on AM (it normally pick up static) or FM.
  6. Audioguru

    Car radio static

    Static sounds from a radio are Amplitude fluctuations which are AM. An AM radio picks up lots of static interference but an FM radio ignors amplitude fluctuations and is quiet. I never use AM radio and always listen to FM radio so I hear no static.
  7. Audioguru

    4017 IC

    The datasheet for the CD4017 shows that with a 12V supply (14.4V in a vehicle) its output current into a 2V red LED is typically 27mA which is enough to smoke its output transistors. (14.4V - 2V) x 27mA= 335mW in each output transistor but the max allowed dissipation in each output transistor is...
  8. Audioguru

    Cant work with ne5534 amp

    You need a high current digital buffer, not an opamp, but a digital buffer or an opamp will work only if we know the spec's it needs. There are many opamps that work using a 5V supply and a gain of 1 like in that circuit. But we do not know the details of the load that the opamp must drive: 1)...
  9. Audioguru

    Harman Kardon 495i

    If the "woofer bounce" is on the channel that has less bass then it is probably a faulty series output capacitor that feeds the speaker. I assume "woofer bounce" is poor damping of the resonance.
  10. Audioguru

    How to make FM modulated signal in SIEMTRIX ? how to configure sffm

    Can't you learn electronics in your own language in your country?
  11. Audioguru

    The Fathom-Sound Project

    If you touch the gap with a coin or sweaty finger then the base current of BOTH transistors will be so high that they are destroyed. Each transistor needs a current-limiting resistor in series with its base and be calculated correctly.
  12. Audioguru

    Cant work with ne5534 amp

    The designer of the circuit did not read the datasheet for the NE5534 op[amp he is using wrongly. The datasheet says the NE5534 opamp will not work when the supply is less than 6V but the video shows 5V. The datasheet also shows that the NE5534 will not work if the gain is less than 3. In the...
  13. Audioguru

    How to make FM modulated signal in SIEMTRIX ? how to configure sffm

    I and most other people here learned electronics and talk about it on forums in our own language. You did not learn electronics and you are trying to talk in a language you do not know. Isn't there a place in your country for you to learn electronics in your own language??
  14. Audioguru

    How to make FM modulated signal in SIEMTRIX ? how to configure sffm

    Why are you posting this on 3 or more forums?
  15. Audioguru

    The Fathom-Sound Project

    Your oscillators and touch switches are missing important current-limiting resistors to prevent the transistors from destruction. You have unlimited NPN collector current going directly into the base of a PNP transistor that usually has a very low allowed current. Your LM386 mixer and power...
  16. Audioguru

    How to wire tweeter to speaker

    I talked about a two-way speaker system (woofer and tweeter) that does not have a midrange speaker. You are talking about a three-way speaker system that has a midrange speaker that needs an additional RC because you do not want the midrange to play bass and also not play high frequencies. You...
  17. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    In most countries.
  18. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    The frequency range is wrong. In a superheterodyne FM radio that has a 10.7MHz IF the local oscillator must tune from 77.3MHz to 97.3MHz or tune from 98.7MHz to 118.7MHz except a little lower in Japan where I think FM station frequencies go down to 76MHz.
  19. Audioguru

    Hello, can somebody help wich transistor is like bfg520

    No. Please study Superheterodyne Receiver Operation. The local oscillator must be the IF frequency below or above the received radio station frequency. The IF frequency of most FM radios is 10.7MHz so read my previous post for the frequency ranges of the local oscillator.
  20. Audioguru

    DC power over coax

    Doesn't an analog video signal need DC coupling for the proper black level? Many, many years ago I used a DC-restorer circuit and a coupling capacitor.
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