## ECEN 1400 - Introduction to Digital and Analog Electronics

### Peter Mathys, Spring 2014

### Problems for Wed. 01-15-14

**Problem 1.1** A 9-cell Li-Ion laptop battery is specified
as having a capacity of 6600 mAh and storing 73 Wh of energy.

**(a)** How many electrons move from the negative to the positive terminal if
a fully charged battery with the above specifications is discharged?

**(b)** What is the voltage of the battery?

**(c)** If a laptop uses 0.9 A, how long can it be powered with a fully
charged battery?

**Problem 1.2** In your lab kit you have resistors with values

1.0k, 1.2k, 1.5k, 1.8k, 2.2k, 2.7k, 3.3k, 3.9k, 4.7k, 5.6k, 6.8k, 8.2k, and

10k, 12k, 15k, 18k, 22k, 27k, 33k, 39k, 47k, 56k, 68k, 82k

where 1.0k stands for 1.0 kilo-ohms (1000 ohms), 1.2k stands for 1.2 kilo-ohms
(1200 ohms), etc.

**(a)** Show how to obtain a 3.0 kilo-ohm resistor by combining (in series
or in parallel) at most two of the resistors from your lab kit. Is your solution
unique?

**(b)** Repeat (a) for a 5.0 kilo-ohm resistor.

©2008, 2013-2014, P. Mathys.
Last revised: 01-14-14, PM.