pmurdock
Paul Murdock
join:2001-09-13
Riverton, UT
| reply to John Galt
Re: hub or switch at solar powered POP?
Here's another one I found.. made by Parvus
»www.parvus.com/products/IODataco···itch104/
Says it is a 1.5 Watt, as opposed to the 2 Watt usage by the other one. Though at 5 volts, the P=IV equation says it will draw 300 mA.. how can that be lower than the 52 mA device that draws 2 Watts.?!?
cheers,
Paul |
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John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp | What is your system voltage?
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A is A |
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pmurdock
Paul Murdock
join:2001-09-13
Riverton, UT
1 edit | It will be run from a 12V sealed gel cell 285 Amp/hour battery that is charged by some photovoltaic cells.. So the 7.5 v supply is better than the 10V minimum requirement.. however 52 mA versus 300 mA doesn't make sense.. well the equation makes sense.. 
for 52 mA switch
P = IV
2 watts = (I)*10 volts -> I = 2/10 -> I = 0.2 amps
for ~300 mA switch
P = IV
1.5 watts = (I)*7.5 volts -> I = 1.5/7.5 -> I = 0.2
so it appears that the parvus one is better.. though 200 mA is a horrible draw to have for both of the switches..  is that a continuous draw..?
I would think that the draw would be higher at a higher voltage since voltage is like "pressure" if you applying a higher pressure more current would want to flow through the system. So why only draw 52 mA @ 24VDC and draw MORE current (~200 mA) @ 10VDC? This is what I don't see.
cheers,
Paul |
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