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Type: Posts; User: FANT

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  1. Replies
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    Closed: Re: Spectrum analyzer range extension and usage

    Go in the biggest chinese selling site and search for D6 spectrum analyzer, hope it will fit your request.

    Mandi
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    Closed: Re: Generating the waveform as in the image

    Use the FY6600 generator and connect the first source to the second generator, first square wave with 2 Hz period, 50 % duty cycle, and the second on/off modulated and carrierfrequency of 27 MHz
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    Closed: chinese generator not working

    Good morning;

    I have bought with aliexpress a signal generator as the link indicated below.
    Powered, no sign of life.
    Contacted the dealer, no answer, and aliexpress refused to press the dealer...
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    Closed: Re: FM modulator using PLL working ???

    The fact is that under the loop frequency you must modulate the crystal of the reference frequency, otherwise the modulation will be acncelled by the loop correction, while above the loop frequency...
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    Closed: Re: Welding machine (need circuit explain)

    It is hard to say without a schematic diagram.

    In any case, the first picture seems to be a recovery diode, the diode that dissipates the energy accumulated into the lekage inductance of the...
  6. Closed: Re: Radio frequency circuit 30 meter to 500 meter at 1.5GHz

    What you mean as -75: 75 Ohm impedance or - 75 dBm received field ?
    Anyway, with 1 W and considering a 0 dB antenna gain (TX + RX ), you have:

    30 meters = 65 dB attenuation, meaning a signal on...
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    Re: How does the price of PCB board work out?

    7. Place where the PCB is produced
    8. Chemical processes on the connectors ( i.e. gold metalization )
    9. Quality processes ( i.e. test on the nail beds )
    10. Delivering (vacuum packed, single pcb...
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    Closed: Re: Voltage stability problem

    If you add the schematic will be better.
    Having this info, can be anything.
    Control loop on open load ?
    Reference voltage that follows the output voltage ?
    Optocouplers not correctly polarized (...
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    [SOLVED]Closed: Re: Acceptable SNR for radio transceiver ICs

    The preamplifier is used to kill the noise figure of the first mixer and filter for noise image rejection, otherwise you will have a receiver with roughly 10 - 11 dB of noise figure, with...
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    [SOLVED]Closed: Re: Acceptable SNR for radio transceiver ICs

    If you add a preamplifier in fron of the receiver, you will have three possible solutions
    - LNA has a noise figure lower than the receiver : In this case you will increase the sensitivity of the...
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    Closed: Re: Load between series capacitors

    Just measung phase between votage and current passing through.
    If you see the meter only with the capacitors, you will see no power adsorbed, otherwise if you will add the light, you will see the...
  12. Closed: Re: Mains overvoltage transients and inductance of the mains

    By their construction, the mains suppressors with a lightning current can have a maximum voltage of 1200 v across the terminals.
    and thios is the same for all the companies.
    personally I use the...
  13. Closed: Re: Mains overvoltage transients and inductance of the mains

    Consider that here in Italy, you have a short circuiti current of 6 kA for house electrical installation, with a mains nominal voltage of 230 Vac, you have an impedance of 0,038 Ohm.

    Nothing is...
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    [SOLVED]Closed: Re: Triac becomes very hot

    You do not mention power of the motor or the type of triac.
    Anyway, a TO220 TRIAC can handle about 2 W in free air, and with this power is quite hot.
    Try with a small heatsink, but with 2 W power...
  15. Closed: Re: Why these two decoupling capacitors de-sens the RX?

    Most probably a self oscillation. Check with the oscilloscope probe.
    Also, during the time the tip of the probe touches the PCB, check for sensitivity.
    Sometimes it happens that the spurius...
  16. Closed: Re: Can I trust a cell phone to report an accurate and precise signal strength?

    Take care that the SS indicated is with the antenna, not the field strenght.
    If you have to trace the field strenght, you need a calibrated antenna and a calibrated receiver.
    On the legal point:...
  17. Closed: Re: ИH-9 NIXIE BARGRAPH TUBE Russian language datasheet (Can anyone translate?)

    It looks like a magic eye used on the old radios to indicate the signal strenght.
    You can find it in many old radios, it works on the grid voltage, that was used to drive the AGC on AM reception.
  18. Closed: Re: Is there any way to prevent a transistor from saturation mode

    If the transistor is an NPN type, use a Shottky diode between base and collector, anode on base.
    This will prevent transistor from saturation.
    Anyway now is plenty of fast switching transistors,...
  19. Closed: Re: Using Electronic Fuses instead of Mechanical Fuses ?

    I fully agree with the previus answer; in atex word the rules are very strict due the thinking and experience made.
    Do not try to overtake the rules, you have no chance to pass the test.
    I.E. if a...
  20. Closed: Re: Hidden Secrets of 3 Terminal Regulators and Precautions to be considered on LM338

    Just insert a reverse biased diode between input and output (i.e 1N4007, anode on output); be careful on the filtering capacitors ( could oscillate,, see data sheet ); do not use an input voltage...
  21. Closed: Re: Is this a good place to discuss progects involving things that go on the roof ?

    it might shot down because the Codes do not allow it or people don't understand etc.

    Sorry if I insist, but this brings to incidents and death.
    Unfortunately I have seen many incidents because...
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    Closed: Re: oscillation in a Power Amplifier

    First I have no info on that transistor described, so I do not know power, etc.
    In any case first try with a piece of ferrite on the input trace, to reduce the Q of circuit, usually it helps. In...
  23. Closed: Re: [moved] Small question confuses me

    Rated current is the current at the nominal torque; peak current is the starting current or the current with locked rotor
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    Re: How to measure AC voltage ?

    For the mains, you can use a voltage divider, but you have to take care that there is no galvanic insulation.
    For the higher voltage you are mentioning, the usual way is to use a reducing...
  25. Closed: Re: Is this a good place to discuss progects involving things that go on the roof ?

    It depends on the regulations existing on your country.
    I.E. in my country, you cannt connect anything stable on mains unless it is not certified and has a CE marking on it.
    Doing something by...
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