Re: HELP!! Need answers for test!!!

["Robertm" <Respond@xxxxxxxxxxxxx>]

"Frank Olson" <Use_the_email_links@xxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:YVGmf.86520$Gd6.37113@xxxxxxxxxxx
> petem wrote:
>> I do not agree and this link will say the same
>>
>> http://www.answers.com/topic/resistor
>>
>> a resistor is limiting current not voltage
>
>
> They're wrong.  A resistor drops voltage and is a voltage limiting device.
> If you (for instance) use a variable resistor to control the speed of a
> fan (or light), the current remains the same regardless of the setting.
> The only thing you're doing is reducing the voltage to the load.

We are also reducing the current if the resistance of the load remains
fixed. A lamp and fan would be more difficult to calculate because impedance
enters into fan calculations, and lamp resistance changes dependent on
element temperature which is dependent on applied voltage and subsequent
current. If we were to assume a resistive load of 12 ohms across a 12 volt
supply, we have one amp flowing. Add a 12 ohm resistor in series with the
load and we now have 6 volts across the limiting resistor and 6 volts across
the load giving us a current of 500 ma through the load.

Bob