ASVAB Electronics Information Practice Test 298638

Questions 5
Topics Capacitors, Circuit Breakers, Resistance, Semiconductors, Series Circuit

Study Guide

Capacitors

Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.

Circuit Breakers

Like fuses, circuit breakers stop current flow once it reaches a certain amount. They have the advantage of being reusable (fuses must be replaced when "blown") but respond more slowly to current surges and are more expensive than fuses.

Resistance

Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional.

Semiconductors

Semiconductors have valence shells that are exacly half full and can conduct electricity under some conditions but not others. This property makes them useful for the control of electrical current.

Series Circuit

A series circuit has only one path for current to flow. In a series circuit, current (I) is the same throughout the circuit and is equal to the total voltage (V) applied to the circuit divided by the total resistance (R) of the loads in the circuit. The sum of the voltage drops across each resistor in the circuit will equal the total voltage applied to the circuit.