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Heat from electronic components

Discussion in 'Electronic Basics' started by Rookie, Nov 26, 2003.

  1. Rookie

    Rookie Guest

    Can someone help me understand heat generation in electronic
    components (IC's, caps, inductors etc)

    I just can't seem to get a handle on the concept. Here is what I know:

    power = V * I (this should work for anything?) - does this mean that
    you can calculate the heat loss from any IC just by knowing its V and
    I requirements? Or do we need to know the nitty gritty details of what
    components are on the IC?

    The only easy one for me is a simple resistor: P = V * I or P = I^2 *
    R etc - this IS the heat dissipation for this component

    I guess the question is if a circuit (IC or whatever) is being fed P =
    V * I power, then does all this energy get dissipated as heat, by
    definition? Electrical power in = heat out?

    thanks much
    confused...
     
  2. RD

    RD Guest

    Unless the circuit produces another form of energy i.e. light (LED) then you
    can apply P=VI just as a resistor as almost all power will converted to
    heat.

    Regards RD
     
  3. That is all there is to it except for a couple details. The I and V
    have to be DC to be measured as average values and then multiplied.
    If AC, they have to be multiplied as instantaneous values and that
    product averaged. This accounts for the energy storage of inductors
    and returns to the driving source twice per cycle.

    There is also an exception for things that convert electric energy to
    some other form besides heat (like motors and lamps). If they were
    100% efficient (which none are) then I*V would just measure their
    energy output in some other form. As it is, I*V measures the power
    entering them, and you have to have some other information to tell
    what fraction of that power is not turning into heat, inside them.
     
  4. I was taught that anything that draws alot of current typically heats up,
    regardless of voltage drops. Something like a fuse is the best example,
    vaporizing at a certain point when too much current is drawn.
     
  5. This is more or less how it works, But It depends on the circuit. The
    idea is Power in = Power out. Due to losses in the circuit some of those
    Power get's converted to heat, So it becomes Power out = Power useful +
    heat out.

    What you should realize is that all conducters has a very small
    resistance which causes losses in power in the form of heat.



    ,Fernan
     
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