Basic Electrical Principles Flashcards

Which direction does conventional current flow in a circuit?

Answer: From positive terminal to negative terminal

By convention, current is defined as flowing from the positive terminal through the external circuit to the negative terminal.

What component stores electrical charge in a circuit?

Answer: Capacitor

A capacitor stores electrical energy as an electric field between two conductive plates separated by an insulator.

Three 9-ohm resistors are connected in parallel. What is the total resistance?

Answer: 3 ohms

For identical resistors in parallel, total resistance = R/n = 9 Ω ÷ 3 = 3 ohms.

What is the primary purpose of a ground wire in an electrical system?

Answer: To provide a safe path for fault current and prevent shock

A ground wire provides a low-resistance return path for fault current, protecting people from electric shock if a fault occurs.

What happens to the brightness of bulbs in a series circuit as more bulbs are added?

Answer: Each bulb gets dimmer

Adding bulbs in series increases total resistance, reducing current through all bulbs, which makes each one dimmer.

Alternating current (AC) differs from direct current (DC) because AC:

Answer: Reverses direction periodically

AC periodically reverses its direction of flow, cycling back and forth, while DC flows continuously in one direction.

A circuit has a 9-volt battery and a resistor. If 0.5 amperes flow, what is the resistance?

Answer: 18 ohms

Using Ohm's Law: R = V/I = 9 V ÷ 0.5 A = 18 ohms.