Interesting point

Discussion in 'General Electronics Chat' started by bluebrakes, Nov 14, 2009.

  1. bluebrakes

    Thread Starter Senior Member

    Oct 17, 2009
    Supposedly the higher the resistance in a circuit the hotter it gets.

    however, why is the case the opposite when you use a resistor accross a battery? the lower the resistance the hotter the resistor gets. :confused:

    The problem came about when my friend was using resistors on his car when he was using LED indicators instead of incandescent type bulbs. The lack of current consumption meant the leds would flash rapidly.

    When I said to him you need to use xx amount of ohms (equiv to the bulb) to stop it but they will get very hot due to their low resistance and may even pop. That's when the arguement started.
  2. Wendy


    Mar 24, 2008
    You are assuming current stays the same. In that case the voltage would also have to rise.

    Generally higher resistance cools things down. Voltage is generally a constant, so current goes down.

    I am assuming you aren't discussing thermal run away in a BJT transistor.
  3. bluebrakes

    Thread Starter Senior Member

    Oct 17, 2009
    no not transistors, just the resistors themselves. The large heatsink mounted 50watt resistors.

    Being a battery the voltage is going to be constant, especially something like a car battery.