1.2 Understanding Direct Current Fundamentals

Which of the following is a characteristic of direct current (DC)?

• The current changes direction periodically

• The current flows in one direction only

• The voltage alternates between positive and negative values

• The frequency is typically 50 Hz

What is the unit of electric current?

• Volt

• Ampere

• Ohm

• Watt

Which device is commonly used as a DC source in electronic circuits?

• Transformer

• Battery

• Inductor

• Capacitor

What is the symbol for direct current in circuit diagrams?

• ~

• =

• /

• -

Which of the following is a common application of DC power?

• Powering household refrigerators

• Operating LED flashlights

• Running ceiling fans

• Powering microwave ovens

Which of the following is a potential hazard of direct current?

• Electric shock

• Magnetic interference

• Radioactive contamination

• Ultraviolet radiation

What is the formula for calculating electrical power in a DC circuit?

Which of the following is NOT a type of DC source?

• Solar cell

• Battery

• Generator with commutator

• Transformer

What is the main difference between DC and AC?

• DC flows in one direction, AC alternates direction

• DC is used for high voltage transmission, AC is not

• DC is always safer than AC

• DC cannot be stored, AC can

Which safety precaution should be taken when working with DC circuits?

• Use insulated tools

• Work with wet hands

• Ignore voltage ratings

• Remove protective gear