COMPREHENSIVE CWB LEVEL 2 STUDY
GUIDE 2026 EDITION MODULES 4, 5, 6, 7, 8,
9, 12, 17, 18, 19 & 22 – PRACTICE
QUESTIONS AND ANSWERS WITH
DETAILED RATIONALES FOR
CERTIFICATION EXAM PREPARATION
When choosing between AC and DC output;
A. the process generally determines the type of current
B. high current output machines are always both AC/DC
C. DC is generally used for very high output applications
D. most supplies are equipped with constant voltage/constant
current options - CORRECT ANSWER -A. the process generally
determines the type of current
Which of the following metals has the lowest electrical resistivity?
A aluminum
B. tungsten
C. copper
D. iron - CORRECT ANSWER -C. copper
,What is the purpose of an inverter?
A. to convert AC current to DC current of the same frequency
B. to convert DC current to high frequency AC current
C. to convert AC current to DC current
D. to convert electrode positive to electrode negative - CORRECT
ANSWER -B. to convert DC current to high frequency AC current
How is power flow analyzed in alternating current circuits?
A. AC circuits can be evaluated the same as DC circuits when RMS
values of voltage
and current are used
B. when analysing AC circuits, inductive and capacitive reactance
must be included
C. average current in an AC circuit is zero and therefore no work is
done
D. the peaks and valleys of sine wave curves balance to zero with
the load - CORRECT ANSWER -C. average current in an AC circuit is
zero and therefore no work is done
Which of the following methods is commonly used to control the
output of a transformer?
A. an auxiliary power supply which feeds the secondary as
required
B. a saturable reactor in series with the output
,C. resistance placed in parallel with the primary of the
transformer
D. taps on the secondary of the transformer - CORRECT ANSWER -D.
taps on the secondary of the transformer
A transformer type welding power source without a rectifier
outputs what type of current?
A. direct current
B. alternating current
C. high frequency current
D. pulsed direct current - CORRECT ANSWER -B. alternating current
When gas tungsten arc welding steels electrode polarity is most
commonly;
A. electrode positive
B. electrode negative
C. alternating current
D. electrode square wave - CORRECT ANSWER -B. electrode negative
A disadvantage of SCR control is that the output is very 'choppy'.
How is the output made more suitable for welding?
A. the output is smoothed out by the addition of capacitors
B. the large inductor or choke will be added to the circuit
, C. the output from an SCR bridge is smooth enough for welding
purposes
D. the diodes added to all SCR controlled machines to prevent
"choppy" output - CORRECT ANSWER -A. the output is smoothed out
by the addition of capacitor
Gas tungsten arc and plasma arc welding power sources are
commonly designed with high frequency units. What does the
high frequency unit do?
A. increases heat input due to the increased frequency which
increases the total time
at high current flow
B. outputs high voltage, low current to create and maintain a
stable conductive path for the flow of power
C. decreases the cleaning action created by electrode negative
polarity present in
alternating current arcs
D. outputs balanced current flow between electrode positive and
electrode negative
half cycles - CORRECT ANSWER -B. outputs high voltage, low current
to create and maintain a stable conductive path for the flow of
power
Gases are not normally electrically conductive. To start an arc;
A. requires high voltage
GUIDE 2026 EDITION MODULES 4, 5, 6, 7, 8,
9, 12, 17, 18, 19 & 22 – PRACTICE
QUESTIONS AND ANSWERS WITH
DETAILED RATIONALES FOR
CERTIFICATION EXAM PREPARATION
When choosing between AC and DC output;
A. the process generally determines the type of current
B. high current output machines are always both AC/DC
C. DC is generally used for very high output applications
D. most supplies are equipped with constant voltage/constant
current options - CORRECT ANSWER -A. the process generally
determines the type of current
Which of the following metals has the lowest electrical resistivity?
A aluminum
B. tungsten
C. copper
D. iron - CORRECT ANSWER -C. copper
,What is the purpose of an inverter?
A. to convert AC current to DC current of the same frequency
B. to convert DC current to high frequency AC current
C. to convert AC current to DC current
D. to convert electrode positive to electrode negative - CORRECT
ANSWER -B. to convert DC current to high frequency AC current
How is power flow analyzed in alternating current circuits?
A. AC circuits can be evaluated the same as DC circuits when RMS
values of voltage
and current are used
B. when analysing AC circuits, inductive and capacitive reactance
must be included
C. average current in an AC circuit is zero and therefore no work is
done
D. the peaks and valleys of sine wave curves balance to zero with
the load - CORRECT ANSWER -C. average current in an AC circuit is
zero and therefore no work is done
Which of the following methods is commonly used to control the
output of a transformer?
A. an auxiliary power supply which feeds the secondary as
required
B. a saturable reactor in series with the output
,C. resistance placed in parallel with the primary of the
transformer
D. taps on the secondary of the transformer - CORRECT ANSWER -D.
taps on the secondary of the transformer
A transformer type welding power source without a rectifier
outputs what type of current?
A. direct current
B. alternating current
C. high frequency current
D. pulsed direct current - CORRECT ANSWER -B. alternating current
When gas tungsten arc welding steels electrode polarity is most
commonly;
A. electrode positive
B. electrode negative
C. alternating current
D. electrode square wave - CORRECT ANSWER -B. electrode negative
A disadvantage of SCR control is that the output is very 'choppy'.
How is the output made more suitable for welding?
A. the output is smoothed out by the addition of capacitors
B. the large inductor or choke will be added to the circuit
, C. the output from an SCR bridge is smooth enough for welding
purposes
D. the diodes added to all SCR controlled machines to prevent
"choppy" output - CORRECT ANSWER -A. the output is smoothed out
by the addition of capacitor
Gas tungsten arc and plasma arc welding power sources are
commonly designed with high frequency units. What does the
high frequency unit do?
A. increases heat input due to the increased frequency which
increases the total time
at high current flow
B. outputs high voltage, low current to create and maintain a
stable conductive path for the flow of power
C. decreases the cleaning action created by electrode negative
polarity present in
alternating current arcs
D. outputs balanced current flow between electrode positive and
electrode negative
half cycles - CORRECT ANSWER -B. outputs high voltage, low current
to create and maintain a stable conductive path for the flow of
power
Gases are not normally electrically conductive. To start an arc;
A. requires high voltage
