LED: Light Emitting Diode Question

[sebugg@presby.edu (Stephen Buggie)]

             LED LIGHT EMITTING DIODE:  WHAT OHM RESISTOR FOR +5V AND +12V?

             QUANTUM LPS52 HARD DISK: WHAT AMPS REQUIRED ON EACH VOLTAGE?



I am proceeding with my plan to move my external hard disk (Quantum LPS52
3.5" HH) from its commercial external box to the classic Apple Disk ][
casing.  The power will come from a surplus Apple ][ power supply connected
by a 6 ft four conductor cord, which will supply the +5V and +12V power
required.

I plan to install two LED lamps on the front panel of the Disk ][ housing
so that I can monitor the power.

QUESTION: What resistor should be wired in series with the LED?  I expect that
the resistor (ohm) value will differ for the two voltages: +5V and +12V.
The higher voltage will require a higher ohms resistance, correct?  Please
specify ohms values for each of the two voltages, +5v and +12v.  I presume
that
I can use even a tiny resistor in series with the LED; perhaps even the 1/8
watt size; is this correct?

Second, I plan to install two fuse-holders on the back panel of the Disk ][,
a fuse on the +5v line and a second fuse on the +12v line.

QUESTION:  What will be the optimum fuse values for the +5v line and the +12v
line?  The answer will depend on the current requirement of the Quantum LPS52
hard disk drive.  I _guess_ that the +5v line powers the electronics while the
+12v line powers the motor.  But does anyone know how much current this
Quantum
pulls from the two voltage lines?   If the current is known, then I will
install fuses just slightly larger than the amperage requirements of the
disk drive.

Please e-mail me at:     sebugg@cs1.presby.edu   Thanks.   Stephen Buggie


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 ** Stephen Buggie  Psych Dept  Presbyterian College   Clinton SC 29325 **
 ** sebugg@presby.edu     IIe/IIc     voice: (803) 833-8337 or 833-1632 **
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.