If the talktime is 4Hrs and standby is 120Hrs,calculate current drawn from battery and power supplied to phone

Question

Been stuck on dthis question for a months.

Need urgent help.

Answer 1

300 mAh seems low for a battery... but anyway:

Let's assume the phone draws 300 mA in standby mode.  In this case the standby time would be 1 hour.

Since Standby time is 120 hrs we can safely say the phone draws an average of 2.5 mA while in standby mode.  300 / 120 = 2.5

Now let's assume a talktime draw of 300mA.   In this case the talktime would be 1 hour.

Since talktime is 4 hours with a 300mAh battery the phone must not draw more than 75mA on average during talktime.  300 / 4 = 75.

These numbers would make a lot more sense if the battery was 3000mAh capacity considering the typical cell phone draws just under an amp (~750mA) at 3.6 vdc during talktime.

Answer 2

Not enough information.

Need to know the battery's storage capacity in amp hours and the effective load resistance of the phones's circuitry.

Current = batt. cap./time

Power = I^2 R

All you can say from the information provided is that the talktime current is 30 times the standby current.