1. 1
POLYTECHNIC OF NAMIBIA
htt p : / /w w w . p o l y t ec h n i c . e d u . n a
SCHOOL OF ENGINEERING
Private Bag 13388, Windhoek, Namibia. Tel: +264 (61) 207 2537 Fax: +264
(61)2072142
DEPARTMENT: ELECTRICAL ENGINEERING
h t tp :// www . p o lyt e c hn ic . e d u . n a/ EE E
School of
Engineering
Department of Electrical
Engineering
ELECTRICAL ENGINEERING
LABORATORIES
Qualification (B.
Eng., 2nd Year)
ELC 520S ELECTRICAL
PRINCIPLES – 124
Laboratory 2: VERIFICATION OF OHM’S LAW,
CURRENT AND VOLTAGE DIVIDER
Pre-lab for lab 2
Lecturer
Al-Mas Sendegeya
Lab assistant
Mr. Elifas Ngonga
Name: Evandro Conceicao
Student Number: 212086561
Student Signature -----------------------------
P re- l a b q u e s t i o n s

2. 2
Question 1
· What is the power dissipated in a resistor?
· Does it depend on the polarity of the source?
Answers
· Power dissipated
·
The power dissipated in a resistor has a relationship with the resistance and the
current through that resistor. According to ohms law R=V/I but Power=V.I
Voltage=R.I
Therefore by substituting Power=R.I.I
=RI2
· Does it depend on the polarity of the source?
These power does not depend on the polarity a negative sign will mean that power
has been lost.
Question 2
· What is a voltage divider what is a current divider
A voltage divider also referred to as a potential divider is a linear circuit that produces an
output voltage which is a fraction of the input voltage.
But voltage division refers to the partitioning of a voltage amongst the components of the
divider when they are in series.
Vt v1
R1 R2
V1=( R1/( R1×R2) ) × Vt
Question 3
· What is a current divider?

3. Answer
A current divider is a simple linear circuit that produces a current which is a fraction of its input
current.
Current division refers to the splitting of current between the branches of the divider. These
components will be connected in parallel.
The current divider rule..
3
R1
I1
R2
I2
I
Vt
Rt= (R1*R2)/(R1+R2)
But V=IR and Total current I=V/(Rt) I1=[R2/(R1+R2)]*It and I2=[R1/
(R1+R2)]*It
Question 4
By using figure 4 as an example circuit. Voltage across
4. Apply the knowledge you have about series and parallel connection of
resistors to determine the effective resistance of circuits given in Figures 4
and 6 (use these resistance values R1 =
2.7-kΩ, R2 = 3.9-kΩ and R3 = 4.7-kΩ
Assistant) between terminals P and Q as in the figure 3.

4. 4
Resistance in series RT=R1+R2+R3
2.7KN+3.9KN+4.7KN
=11.3KN is the equivalent resistance
Rt=[(R1 R2) R3 ]
= (2.7KN*3.9KN)/(2.7KN+3.9KN) 4.7KN
=(1.595KN*4.7KN)/(1.595+4.7KN)
=1.19KN is the equivalent resistance
.