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Need electric current modulator

  1. Sep 30, 2014 #1
    Could you advise me, which type of device could be purchased in general electronic stores (or at least in specialized ones) and which are capable to modify electric current in wide spectrum? Desirable in small power range. Such as to set a pulse width, harmonic, frequency, pulse duration, power and similar modulations? Desirable it needs to have a couple of outputs which look like an electrodes. What could be a name of a such device?
     
  2. jcsd
  3. Sep 30, 2014 #2

    davenn

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    Gold Member

    that's a pretty broad request

    can you be a bit more specific with your project so that better responses may be forthcoming :)

    cheers
    Dave
     
  4. Oct 1, 2014 #3

    Baluncore

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    Science Advisor

    A "signal generator" of some sort?
     
  5. Oct 1, 2014 #4
    If you are in the U.S. you should be aware of the FCC regulations regarding doing that.


    upload_2014-10-1_7-52-30.png
     
  6. Oct 1, 2014 #5

    Baluncore

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    Science Advisor

    The OP is asking for the “name” of a “low power” device and has not suggesting a transmitter to radiate EM waves. Signal generators do not need licences, even in the USA.
     
  7. Oct 1, 2014 #6
    The OP did not indicate either the frequency or power that he was intending to feed into the AC power lines. That is why I suggested he be aware of the regulations.

    §15.107 Conducted limits.

    (a) Except for Class A digital devices, for equipment that is designed to be connected to the public utility (AC) power line, the radio frequency voltage that is conducted back onto the AC power line on any frequency or frequencies within the band 150 kHz to 30 MHz shall not exceed the limits in the following table, as measured using a 50 μH/50 ohms line impedance stabilization network (LISN). Compliance with the provisions of this paragraph shall be based on the measurement of the radio frequency voltage between each power line and ground at the power terminal. The lower limit applies at the band edges.

    Frequency of emission (MHz)


    Conducted limit (dBμV)

    Quasi-peak


    Average

    0.15-0.5


    66 to 56*


    56 to 46*

    0.5-5


    56


    46

    5-30


    60


    50

    *Decreases with the logarithm of the frequency.

    (b) For a Class A digital device that is designed to be connected to the public utility (AC) power line, the radio frequency voltage that is conducted back onto the AC power line on any frequency or frequencies within the band 150 kHz to 30 MHz shall not exceed the limits in the following table, as measured using a 50 μH/50 ohms LISN. Compliance with the provisions of this paragraph shall be based on the measurement of the radio frequency voltage between each power line and ground at the power terminal. The lower limit applies at the boundary between the frequency ranges.

    Frequency of emission (MHz)


    Conducted limit (dBμV)

    Quasi-peak


    Average

    0.15-0.5


    79


    66

    0.5-30


    73


    60

    (c) The limits shown in paragraphs (a) and (b) of this section shall not apply to carrier current systems operating as unintentional radiators on frequencies below 30 MHz. In lieu thereof, these carrier current systems shall be subject to the following standards:

    (1) For carrier current systems containing their fundamental emission within the frequency band 535-1705 kHz and intended to be received using a standard AM broadcast receiver: no limit on conducted emissions.

    (2) For all other carrier current systems: 1000 μV within the frequency band 535-1705 kHz, as measured using a 50 μH/50 ohms LISN.

    (3) Carrier current systems operating below 30 MHz are also subject to the radiated emission limits in §15.109(e).

    (d) Measurements to demonstrate compliance with the conducted limits are not required for devices which only employ battery power for operation and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. Devices that include, or make provision for, the use of battery chargers which permit operating while charging, AC adaptors or battery eliminators or that connect to the AC power lines indirectly, obtaining their power through another device which is connected to the AC power lines, shall be tested to demonstrate compliance with the conducted limits.

    [54 FR 17714, Apr. 25, 1989, as amended at 57 FR 33448, July 29, 1992; 58 FR 51249, Oct. 1, 1993; 66 FR 19098, Apr. 13, 2001; 67 FR 45670, July 10, 2002]
     
  8. Oct 1, 2014 #7

    berkeman

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    Staff: Mentor

    Interesting point, skeptic2. It hadn't occurred to me that he might be wanting to experiment with Powerline Communications (PLC). If that is his intent, your advice is definitely important. Guess we'll just have to wait for Stanley to get back to us with more details about what he is wanting to do...
     
  9. Oct 2, 2014 #8

    Baluncore

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    Where did the OP indicate an intention to modulate the AC power lines?
     
  10. Oct 2, 2014 #9

    berkeman

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    Staff: Mentor

    He wasn't specific enough yet to tell much of anything about his intended application. I got the impression he wanted to add modulation on top of some existing current, rather than use a signal generator to make a current waveform. But until the OP decides to actually come back and read this thread, we don't have much of an idea what he wants to do. Sigh.
     
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