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Question
Why -48V dc power supply using in telecom field?
 Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
- 48 VDC is used in telecom to prevent corrosion or
electrolysis. If you use +48VDC there are free electrons
raging to go somewhere, as each electron is lost, you lose
what is part of a molecule of copper, thus the copper
corrodes away, lines corrode away until they break! -48VDC
wants electrons so it attracts molecule = no loss of copper
or corrosion/electrolysis.
 
Is This Answer Correct ?    28 Yes 2 No
R. D.
 
Answer
# 2
Basically for any electronic device it needs a DC supply as
a source power the different components inside it.
everybody knew that the telephone in our houe will not
contain any supply line (speaking about basic model) other
than the one that comes from the exchange. but how is the
Electronic board inside the telephone is working?

this line carries a DC voltage of 48V (42V to $8V approx).
this voltage supplies power to the components inside the
telephone as well as carries the voice signals from
exchange to our phone and vice versa.
 
Is This Answer Correct ?    14 Yes 7 No
Cnu
 
 
 
Answer
# 3
positive is earthed ? 
Is This Answer Correct ?    5 Yes 4 No
K.prakashchandra
 
Answer
# 4
Equipments which is used in telecom field Designed
for -48volts
 
Is This Answer Correct ?    6 Yes 9 No
Shivareddy
 
Answer
# 5
Why Because Earthing contrctor Earn money so that 
Is This Answer Correct ?    7 Yes 12 No
U.chandarasekar
 
Answer
# 6
because all of the electronics equipments used in telecom
field(bts,tx-rx rack,mux etc)are working in dc supply,so
that this is happen.
 
Is This Answer Correct ?    4 Yes 9 No
Ratikanta Mekap
 
Answer
# 7
no idea??? 
Is This Answer Correct ?    8 Yes 14 No
Vinayak.kadam
 

 
 
 
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