Chretien said:
Im just trying to confirm my understanding of Parallel circuits and Watts
calculations when using resistors.
This is not for any project. But sometimes projects call for 1/2 watt
resistors. It means I have to run to the store since I don't keep any of
them on hand. This would be a way around this.
Are my simple calculations right?
Under the assumption that the rating for the individual
resistors remains unchanged when in "parallel", then
your written statement is not false.
Something to keep in mind, however, is that the rated
dissipation holds for certain standard conditions that
may not pertain when you parallel the parts. As an
example, significant heat flows out of a lead-mounted
resistor to the circuit board, keeping the resistor's
temperature lower than if that path did not exist. If
you connect two resistors in parallel and mount them
in the hole pair intended for a single resistor, the heat
flow into the circuit board will not double and there
will be a greater temperature rise for the part bodies.
And if N paralleled resistors are bunched together,
they will not be cooled by air as well as they would
be if mounted in the standard fashion.
Basically you can double the wattage if you put two or more resistors in
parallel.
A stronger statement, assuming you equalize the
dissipation in N resistors, (and retaining the "no
change in rating" assumption), is that the rated
dissipation is multiplied by N.
This will of course decrease the R Value.
I would hope so.
[Cut some resistor diagrams.]