1. True or false: A series circuit is also known as a voltage divider
circuit (True)
2. True or false: The voltage drop across a series circuit is
proportional to the value of the resistor. (True, if R increase
the voltage drop across R increase)
3. State the voltage divider formula with the aid of a circuit
diagram.
 R1 
V1  
V
 R1  R 2 
 R2 
V2 
V
 R1  R 2 
4. Which component can be used as a variable voltage divider?
Variable resistor / Potentiometer
5. List the three basic problems that can occur with components in
a series circuit.
Problems in series
circuits
A
component will
open
a component’s
value will change
over a period of
time
a component will
short
6. How can an open component be detected in a series circuit?
Using the example:
Since all the source
voltage is dropped across
lamp 3, it’s open.
7. True of false: If a series connected resistor’s value were to
decrease, the voltage drop across that same resistor would
increase. (False, if R decrease the voltage drop across R
decrease)
8. How could a shorted component be detected in a series circuit?
Using the example:
Since Lamp 2 is off and
V2 is zero, then lamp two
is shortened
9. The voltage divider formula states that the voltage drop across a
resistor or multiple resistors in a series circuit is equal to the ratio of
that _____________ to the ______________ multiplied by the
________________.
a) Resistance, source voltage, total resistance.
b) Resistance, total resistance, source voltage.
c) Total current, resistance, source voltage.
d) Total voltage, total current, resistance.
9. Calculate the value of resistors needed to divide up a 90 V
source to produce 45 V and 60V outputs, with a divider circuit
current of 1 A.
V = I*R
V 1 45

 45
I1 1
V 2 60
R2 

 60
I2 1
R1 
10 . If R1 = 4.7 kΩ and R2 = 6.4 kΩ and both are connected across
a 9 V source, how much voltage will be dropped across R2?
4.7 k


V1  
 * 9  3.81 v
 4.7 k  6.4k 
6.4k


V2 
 * 9  5.18 v
 4.7 k  6.4k 
11.
If three equal value resistors are series connected across a
dc power supply adjusted to supply 10 V, what percentage of
the source voltage will appear across R1? V1=(10/3)v
12.
If three lamps are connected across a 9 V battery in series,
and the filament in one of the lamps burned out, causing an
open in the lamp, would the other lamps be ON? Explain why.
No, because the circuit is open and the current will not
flow
13.
If one of three series-connected lamps is shorted, will the
other two lamps be on? Explain why. Yes, because the circuit
is close and the current will flow
14.
When one resistor in a series string is open, explain what
would happen to the circuit’s:
a) Current. (Zero)
b) Resistance. (Increase)
c) Voltage across the open component. (All the source voltage
will be dropped across the open component)
d) Voltage across the other components. (Zero)
15.
When one resistor in a series string is shorted, explain
what would happen to the circuit’s:
a) Current (increase)
b) Resistance. (Decrease)
c) Voltage across the short component. (zero)
d) Voltage across the other components. (increase)
16.
Redraw the circuit below and add one more lamp
connected in series.
a) Will the lamp become brighter
or dimmer when more lamps are
connected in series?
More lamps  R Increase  I
decrease  the lamps are
dimmer
b) What happen to the ammeter
reading now? Read less current
c) If one of the lamps in the
circuit fails what happen to the
other lamp?
If the lamp is open , the
circuit will be open, and the
other lamps will be off
d) Repeat the questions with a
lamp connected in parallel.