The Basic lessons · Basic electronics and theory · B-005-003

Understanding Power, Circuits, and Safety

Learn how to measure the rate of energy use in watts and understand the formula connecting voltage and current. Discover the critical differences between open and short circuits to keep your equipment safe.

This lesson is part of SignalPrep Pro. The subsection's 11 exam questions are free to practise: practise B-005-003.

What this subsection asks

• What term describes the rate at which electrical energy is used?
• If you have light bulbs marked 40 watts, 50 watts, 60 watts and 100 watts, which one will consume electrical energy at the highest rate?
• What is the basic unit of electrical power?
• A circuit consists of a battery and load resistor. What circuit malfunction would cause no current to be drawn from the battery?
• Which electrical circuit draws too much current?
• Power is expressed in:
• Which of the following two quantities should be multiplied together to find power?
• Which two electrical units multiplied together give the unit "watts"?
• A resistor in a circuit becomes very hot and starts to burn. This is because the resistor is dissipating too much:
• When speaking of electrical circuits, what does the term "continuity" mean?
• You have acquired a transceiver and connected it to a power supply. When you switch on the power supply, its fuse blows immediately. What circuit malfunction caused the fuse to blow?