No.	Question	A	B	C	D	Answer
75	Identify three arc-welding power supplies	A. alternator, generator, tachometer	B. tachometer, generator, rectifier	C. transformer, rectifier, generator	D. none of the above	A B C D
76	Direction of current flow (polarity) can be chosen when using	A. a DC power source	B. a transformer	C. all welding power sources	D. an AC power source	A B C D
77	Arc welding with alternating current, will eliminate	A. air pollution	B. magnetic arc blow	C. spatter	D. voltage loss	A B C D
78	Which is the most commonly used power source for GMAW welding	A. AC transformer	B. DC constant-current rectifier	C. an engine driven generator	D. DC constant-voltage rectifier	A B C D
79	How is amperage controlled on a GMAW welding machine	A. gas flow	B. gun trigger	C. stick-out	D. wire feed setting	A B C D
80	What type of welding current is most efficient for GMAW	A. ACHF	B. AC	C. DCRP	D. DCSP	A B C D
81	In direct current (DC) welding, the elctrons' in the welding circuit always travel	A. from negative to negative	B. from negative to positive	C. from positive to positive	D. from positive to negative	A B C D