ATT COMP QUESTIONS AND SOLUTIONS MARKED A+
✔✔A complete short in the secondary transformer will ____________ secondary
voltage. - ✔✔eliminate
✔✔Current flowing through a relays contacts in one direction can only cause what
failure? - ✔✔Coned and cratered contacts.
✔✔What tool should be used to clean relay contacts? - ✔✔A burnishing tool.
✔✔How do you fix a sealed relay? - ✔✔Replace the entire relay.
✔✔What does quiescent mean? - ✔✔Inactive; at rest, but ready to operate.
✔✔Power supplies does what? - ✔✔Converts AC power to DC power.
✔✔A power supply contains five sections. What are they? - ✔✔Input, rectifier, filter,
regulator and protection.
✔✔Power supply input - ✔✔Applies AC signal.
✔✔Power supply rectifier - ✔✔Converts AC to pulsating DC.
✔✔Power supply filter - ✔✔Changes pulsating DC to smooth DC.
✔✔Power supply regulator - ✔✔Maintains output voltage.
✔✔Power supply protection - ✔✔Prevents damage to power supply if load shorts.
✔✔Which two parts of a power supply are optional? - ✔✔Regulator and protection.
✔✔There are three types of rectifiers. What are they? - ✔✔Half wave, full wave, bridge.
✔✔Describe a half wave rectifier. - ✔✔1 diode. Looks like a filter.
✔✔What is the output frequency of a half wave rectifier? - ✔✔Same as input.
✔✔How many diodes does a full wave rectifier have? - ✔✔Two.
✔✔Why is full wave more efficient than half wave? - ✔✔It uses the entire input.
✔✔What is the output frequency of both a full wave and bridge rectifier? - ✔✔Twice the
input frequency (180° out of phase).
, ✔✔How many diodes does a bridge rectifier have? - ✔✔Four.
✔✔Which internal IC can produce signals that show three different volt levels? -
✔✔Short between pins other than VCC and ground
✔✔TS relays and switches, sealed component and 2 types - ✔✔just replace entire
component, faulted mag coils and contacts
✔✔relays and swithces contacts TS, NO NC - ✔✔coned or cratered (burned and pitted)
burnishing tool, prevents out when E and prevents out when de E.
✔✔Electrical TS common faults - ✔✔open or short, LED will not illuminate if open or
shorted
✔✔Procedure for electrical TS - ✔✔is cot op normal? measure Vout observe LEDs
Setup okay? check inputs okay
Calc/measure
check results (repair fault and check again)
✔✔What are three steps for repairing digital systems? - ✔✔Fault detection, isolation,
and correction.
✔✔An IC's internal malfunctions make its operation _______________. -
✔✔unpredictable
✔✔What are the three most common IC faults? - ✔✔Opens, shorts, and faulty power
supply units.
✔✔What component changes color to indicate an element change is needed in dry air
systems? - ✔✔Telltale oil filters.
✔✔What type of cooling is used in sealed enclosures? - ✔✔Air-to-air.
✔✔What cooling system uses chilled water for both standby and normal operation? -
✔✔Type 3.
✔✔Signal tracing - ✔✔If no fault found after voltage or current measurements, next
trace signal with a logic probe.
✔✔Two types of signal tracing? - ✔✔Sequential and half splitting.
✔✔What is the purpose of a transformer? - ✔✔To increase or decrease voltage
depending on requirements of the load.
✔✔A complete short in the secondary transformer will ____________ secondary
voltage. - ✔✔eliminate
✔✔Current flowing through a relays contacts in one direction can only cause what
failure? - ✔✔Coned and cratered contacts.
✔✔What tool should be used to clean relay contacts? - ✔✔A burnishing tool.
✔✔How do you fix a sealed relay? - ✔✔Replace the entire relay.
✔✔What does quiescent mean? - ✔✔Inactive; at rest, but ready to operate.
✔✔Power supplies does what? - ✔✔Converts AC power to DC power.
✔✔A power supply contains five sections. What are they? - ✔✔Input, rectifier, filter,
regulator and protection.
✔✔Power supply input - ✔✔Applies AC signal.
✔✔Power supply rectifier - ✔✔Converts AC to pulsating DC.
✔✔Power supply filter - ✔✔Changes pulsating DC to smooth DC.
✔✔Power supply regulator - ✔✔Maintains output voltage.
✔✔Power supply protection - ✔✔Prevents damage to power supply if load shorts.
✔✔Which two parts of a power supply are optional? - ✔✔Regulator and protection.
✔✔There are three types of rectifiers. What are they? - ✔✔Half wave, full wave, bridge.
✔✔Describe a half wave rectifier. - ✔✔1 diode. Looks like a filter.
✔✔What is the output frequency of a half wave rectifier? - ✔✔Same as input.
✔✔How many diodes does a full wave rectifier have? - ✔✔Two.
✔✔Why is full wave more efficient than half wave? - ✔✔It uses the entire input.
✔✔What is the output frequency of both a full wave and bridge rectifier? - ✔✔Twice the
input frequency (180° out of phase).
, ✔✔How many diodes does a bridge rectifier have? - ✔✔Four.
✔✔Which internal IC can produce signals that show three different volt levels? -
✔✔Short between pins other than VCC and ground
✔✔TS relays and switches, sealed component and 2 types - ✔✔just replace entire
component, faulted mag coils and contacts
✔✔relays and swithces contacts TS, NO NC - ✔✔coned or cratered (burned and pitted)
burnishing tool, prevents out when E and prevents out when de E.
✔✔Electrical TS common faults - ✔✔open or short, LED will not illuminate if open or
shorted
✔✔Procedure for electrical TS - ✔✔is cot op normal? measure Vout observe LEDs
Setup okay? check inputs okay
Calc/measure
check results (repair fault and check again)
✔✔What are three steps for repairing digital systems? - ✔✔Fault detection, isolation,
and correction.
✔✔An IC's internal malfunctions make its operation _______________. -
✔✔unpredictable
✔✔What are the three most common IC faults? - ✔✔Opens, shorts, and faulty power
supply units.
✔✔What component changes color to indicate an element change is needed in dry air
systems? - ✔✔Telltale oil filters.
✔✔What type of cooling is used in sealed enclosures? - ✔✔Air-to-air.
✔✔What cooling system uses chilled water for both standby and normal operation? -
✔✔Type 3.
✔✔Signal tracing - ✔✔If no fault found after voltage or current measurements, next
trace signal with a logic probe.
✔✔Two types of signal tracing? - ✔✔Sequential and half splitting.
✔✔What is the purpose of a transformer? - ✔✔To increase or decrease voltage
depending on requirements of the load.
