# help needed

• Aug 11th 2013, 12:41 PM
fatherjack
help needed
A typical sensor node has a transmit duty cycle of 3% and draws a current of 1.53 mA while it is in the active part of the duty cycle, and negligible current while in the inactive part of the duty cycle. On average, the node sends 375 bits of data per transmission and each transmission takes 33.0 ms.
• i.How long does each node transmit for in every hour? Express your answer in seconds.
• ii.If each sensor node has a battery with a capacity of 2510 mAh, how long a transmission is this battery capable of powering before it must be recharged or replaced? Express your answer in seconds in scientific notation.
• iii.At what data rate is data transferred in each transmission? Express your answer in kbps.

• Aug 11th 2013, 04:05 PM
chiro
Re: help needed
Hey fatherjack.

Can you show us what you have tried? (Hint: If something transmits for 3% of an hour, what is that in minutes/seconds?)
• Aug 12th 2013, 05:37 AM
fatherjack
Re: help needed
when I try to do Qu.1 I get 108 but I am not happy with that answer. Am I right if not what should I do
• Aug 12th 2013, 04:15 PM
chiro
Re: help needed
If you have something that operates at 3% of the total time, then 3% of an hour = 0.03 * 3600 seconds = 108 seconds or just under two minutes (which is what you got, but make sure you label the correct units).