Checkpoint: T0A — HAM Trainer

T0A01 Which of the following is a safety hazard of a 12-volt storage battery that lacks internal protection circuitry?

A Touching both terminals with your hands can cause electrical shock B Shorting the terminals can cause burns, fire, or an explosion C RF emissions from a nearby transmitter can cause the electrolyte to emit poison gas D All these choices are correct

T0A02 What health hazard is posed by electrical current flowing through the body?

A It may cause injury by heating body tissue B It may disrupt the electrical functions of cells C It may cause involuntary muscle contractions D All these choices are correct

T0A03 In the United States, what circuit does black wire insulation indicate in a three-wire 120 V AC cable?

A Neutral B Hot C Equipment ground D Negative

T0A04 What is the purpose of a fuse in an electrical circuit?

A To prevent power supply ripple from damaging a component B To remove power in case of an overload C To limit current and prevent shocks D All these choices are correct

T0A05 Why should a 5-ampere fuse never be replaced with a 20-ampere fuse?

A The larger fuse would be likely to blow because it is rated for higher current B The power supply ripple would greatly increase C Excessive current could cause a fire D Voltage drop in the higher current fuse could result in excessively low voltage to the device

T0A06 What is a good way to guard against electrical shock at your station?

A Use three-wire cords and plugs for all AC powered equipment B Connect all AC powered station equipment to a common safety ground C Ensure all capacitors used for high-voltage DC are fully discharged before working inside equipment D All these choices are correct

T0A07 Where should a lightning arrester be installed in a coaxial feed line?

A At the output connector of a transceiver B At the antenna feed point C At the AC power service panel D On a grounded panel near where feed lines enter the building

T0A08 Where should a fuse or circuit breaker be installed in a 120V AC power circuit?

A In series with the hot conductor only B In series with the hot and neutral conductors C In parallel with the hot conductor only D In parallel with the hot and neutral conductors

T0A09 What should be done to all external ground rods or earth connections?

A Waterproof them with silicone caulk or electrical tape B Keep them as far apart as possible C Bond them together with heavy wire or conductive strap D Tune them for resonance on the lowest frequency of operation

T0A10 What hazard exists when rapidly charging or discharging an unprotected battery?

A Overheating or out-gassing B Excess output ripple C Electric shock D Overvoltage

T0A11 What hazard exists in a power supply immediately after turning it off?

A Circulating currents in the dc filter B Leakage flux in the power transformer C Voltage transients from kickback diodes D Charge stored in filter capacitors

T0A12 Which of the following precautions should be taken when measuring high voltages with a voltmeter?

A Ensure that the voltmeter has very low impedance B Ensure that the voltmeter and its leads are rated for use at the voltages being measured C Ensure that the circuit is grounded through the voltmeter D Ensure that the voltmeter is set to the correct frequency