Noise from unplugged power supply :S

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Discussion Overview

The discussion revolves around noise issues experienced with a CCD camera that incorporates a Peltier element, specifically focusing on noise emanating from the power supply even when it is not plugged in. Participants explore potential causes and solutions related to electrical interference and grounding.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes experiencing noise from the power supply of a CCD camera even when it is unplugged, raising questions about the source of the noise and its relationship to the power connection.
  • Another participant suggests that the noise could be 60/50 Hz interference from power lines and recommends using shielded wire and ensuring an Earth ground for the power supply.
  • A later reply indicates that wrapping the cable in tin foil significantly reduced the noise, suggesting that shielding is effective.
  • The original poster notes that while the noise has improved with shielding, it remains at an unacceptable level and seeks further solutions.

Areas of Agreement / Disagreement

Participants generally agree that the noise is likely related to electrical interference and that shielding can help reduce it. However, the discussion remains unresolved regarding the effectiveness of the current solutions and whether additional measures are needed.

Contextual Notes

The discussion does not clarify the specific characteristics of the noise or the exact nature of the electrical interference. There are also unresolved questions about the effectiveness of grounding and the limitations of the current shielding methods.

Kawakaze
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I have a ccd camera that I put a peltier element into, and there is noise from the power supply, even when it isn't plugged in. Just plugging the jack in gives noise, I tried the bypassing thing with a capacitor with no effect. Plugging the PSU in gives no change. I tried moving the power supply around and this makes no difference plugged in or not, any ideas? If the noise is from the power to to camera from the usb port, why would it only appear when i put the jack in? I really am confused with this.

The case is plastic, and i just noticed that when you even touch the 0v pin of the socket for the jack with a metal object, the noise comes back.
 
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It's probably 60/50 Hz noise from power lines, etc. Have you tried using shielded wire from the supply? Is there an Earth ground on the supply? I would think that the project should be in a metal box so as to shied your project as well as the wiring.
 
You were right, I just wrapped the cable up in tin foil and the noise was almost gone. Shielded cables it is :)

Thanks so much for your help!
 
I just did some more testing, the noise is much better but it is still too much. Is there anything else to be done? Thanks :)
 

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