Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Flashlight



Bernard Cleyet wrote:

I prefer the use of the word cell(s). This also affords the opportunity
to present the distinction between primary and secondary cells.

Thanks. Here is paragraph 15 again; it has just been added to the draft
of my essay.

15) Power is the rate at which energy is converted from one
form to another; the unit of power, watt, is joule per second. Is
the P=U*I formula consistent with this definition? The answer
is "yes" because volts are joules per coulomb (V=J/C) and amperes
are coulombs per second (A=C/s). Clearly, the product of U and I
shows how much energy (joules) is either gained or lost by circulating
charges in one second. This can be verified by algebraic manipulation
of units: 1V*1A=1J/C*1C/s=1J/s=1W. Circulating charges gain energy
inside the cells and loose energy outside the cells. This is the central
idea of an electric circuit. Lost energy increases the temperature of
wires and may appear in the form of light (from a lamp), in the form
mechanical energy (in a motor), etc. The circuit element in which
charges gain energy is usually referred to as an electric source or
an electric generator. Chemical cells are examples of generators.
Solar cells, wind cells and large "electromagnetic cells" can also
be used as sources of difference of potential.