9v battery vs. 6 1.2v battery pack 'noise'

Discussion in 'Power Electronics' started by jcurione, Jul 4, 2016.

  1. jcurione

    Thread Starter New Member

    Jul 4, 2016
    Hello everyone,
    - - Sorry, title should say 1.5 not 1.2v - -
    I'm new here, learning as I go. (I normally work in the medical field, so I'm a novice with electronics). I just invented and built a device that I'm now getting ready to have tested for unintentional emissions. It is an xband motion detector and I am using components with FCC modular approval inside. The microprocessor is just an arduino Uno using 5v.
    My question is this: Is there any difference in 'noise' for emission testing if I use a 9v battery vs. a 6 1.5v battery pack?
    Sorry if this is a dumb question, I am still learning.
    Thank you for your time and help!

  2. DickCappels


    Aug 21, 2008
    If the question is about unintentional radiation, the answer is probably "yes" but you won't find out what the difference is before testing it in your own sytem.

    Reasoning: The battery pack will be part of the "antenna" system for the unintentional radiator and its effect on the signal (perhaps it is a shield or perhaps it causes some directivity) depends on everything else in your system.
  3. Picbuster

    Active Member

    Dec 2, 2013
    Unwanted Radiation and immunity is difficult. Method of measurement, environment to measure in and equipment to use are laydown in the EMC directive. One of the main problem is: what is the influence of the used measurement equipment's?
    Any wire (pcb track) has its own resonance frequency and could start resonating and create sum and diff frequencies with other components/ wires.
    Acting as an antennae it could sweep up the, unwanted, amplitude.
    Shielding is not the best method. To avoid unwanted frequencies make shortcuts for them. (caps/coils and a proper pcb layout)
    Using FCC approval for all parts will not ensure approval hence some could interfere with other approved parts.
  4. jcurione

    Thread Starter New Member

    Jul 4, 2016
    Thank you for your help. I know using FCC approved parts doesn't ensure approval thus the testing. I have read one of the major causes of unintentional radiation is through wiring. Would it make a difference if I used shielded wire in my device?
    Regarding the battery issue, do you think using a single 9v battery as opposed to a six 1.5v battery pack might be less noisy as it would be a smaller unit overall and therefore maybe a smaller "antenna"?
    Also, apologize for asking but what are caps/coils? Does this mean capacitors?
    Thanks again everyone, I greatly appreciate your help!