UNIT 34 REVIEW QUESTIONS ANSWER KEY GO BACK TO INDEX
34-1) A fixed resistor has the following color bands – orange, red, brown, gold. What
is the rated resistance?
34-2) A fixed resistor has the following color bands – orange, red, gold, gold. What is
the rated resistance?
34-3) Does a capacitor lose its charge once it is disconnected from the power source?
34-4) How do ceramic and mica capacitor mfd ratings compare to paper and film
capacitors?
34-5) How do motor start capacitors differ from motor run capacitors?
34-6) Why are some run capacitors marked with a red dot?
34-7) What is the first step in testing a capacitor?
34-8) What is the control voltage used by most residential HVACR equipment?
34-9) What is a center tapped transformer?
34-10) What is an isolation transformer?
34-11) Why are transformer cores laminated?
34-12) Do transformers operate more or less efficiently when fully loaded? Explain
your answer.
Efficiencies for transformers are higher when they operate more fully
34-13) What is the advantage of a circuit breaker as compared to a fuse?
34-14) What is a proximity switch and how does it operate?
34-15) What type of applications is a close-on-rise thermostat normally used for?
34-16) What system functions does a low-voltage thermostat normally control?
34-17) What two manual switches are found on most low-voltage thermostats?
34-18) What types of systems use staging thermostats?
34-19) What do modern electronic thermostats use to sense temperature?
34-20) What types of material are used to sense humidity in humidistats?
34-21) What three ratings should always be matched when changing fuses?
34-22) What type of fuses should be used to protect motor circuits?
34-23) What is a relay?
34-24) What is the cut-out for a close-on-rise pressure switch with a cut-in setting of
45 psig and a differential of setting of 20 psi?
34-25) On a close-on-rise pressure switch, what should the differential be set for a
cut-out of 15 psig if the cut-in setting is 25 psig?
34-26) Consider basic relay logic. What is meant by an AND function? What is
meant by an OR function?
34-27) What are the major differences between relay and solid state logic?
34-28) What is a semiconductor material?
34-29) What is a diode?
34-30) What is a silicon rectifier?