over current protection

Discussion in 'The Projects Forum' started by antony.prathiban, May 20, 2008.

  1. antony.prathiban

    Thread Starter Member

    May 14, 2008
    24
    0
    how ptc thermistors are used for over current protection and also for liquid level measurement?
    please explain.
     
  2. pradeeba

    Active Member

    Feb 27, 2008
    104
    0
    PTC's are made of materials so that, increase in electrical resistance when temperature increases. As the temperature increases, the resistance increases, so less current flows, there by avoiding inrush of current.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    If you had two resistors in a voltage divider network; one fixed, one a PTC thermistor, both would be warmed by the current passing through them, making them hotter than the ambient air temperature. If they were then immersed in a liquid, the PTC resistor's being chilled would reduce it's temperature, thus it's resistance. This would be measureable by voltage across the divider.
     
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