ASVAB Electronics Information Study Notes

General Information

• Subject: Electronics Information
• Passing Score: 800
• Time Limit: 120 minutes
• File Version: 1.0

Key Questions and Answers

Basic Concepts

• Rotor of a Generator: Moves inside a magnet.
• AC Abbreviation: Stands for alternating current.
• Least Resistance Material: Silver has the least resistance compared to wood, iron, and rubber.
• Ohm's Law: Voltage (V) = Current (I) x Resistance (R). Example: With resistance 100 ohms and current 0.1 amperes, V = 10 volts.
• Ohmmeter Usage: Measures resistance.
• Solid State Diodes: Require less operating power compared to tubes.
• Household Voltage: Typically 110V.
• Electromotive Force: Another term for voltage.

Circuit Components and Functions

• Rectifier vs. Inverter: Rectifier converts AC to DC; inverter converts DC to AC.
• Wire Diameter: Larger number indicates smaller diameter (e.g., #12 wire is thinner than #6).
• Battery Connections:
  • Series increases voltage.
  • Parallel increases current.
  • Series-parallel can achieve specific voltage and current combinations.
• Ohm's Law Application: Example calculation for voltage with known current and resistance.
• Subatomic Particle for Electricity: Electrons are responsible for electricity.

Safety and Operation

• Fuse Ratings: Using a fuse with a higher current rating than required is unsafe.
• Capacitors:
  • Retain charge even after power is removed.
  • Must be discharged safely before handling.
• Thermocouple Function: Acts as a thermal sensor to open or close circuits at certain temperatures.

Additional Concepts

• Conductors and Insulators:
  • Good Conductors: Metals like copper and silver.
  • Poor Conductors: Materials like rubber and marble.
  • Insulators have few free electrons, making them poor conductors.
• Diode Function: Allows current to flow in one direction, similar to a one-way street in a city.
• Transistor Function: Acts like a gate in an electronic circuit.
• Magnetic Concepts:
  • Reluctance and permeability are measures of magnetic properties
  • Retentivity and magnetic flux are additional terms related to magnetism.

Circuit Symbols

• Various Circuit Elements:
  • Resistor: Symbol for resistance.
  • Unconnected Wires: Symbol for wires not connected.
  • Ground: Symbol for grounding.
  • AC Power Supply: Symbol for alternating current source.
  • Diode: Symbol for a diode.

Practical Examples

• Christmas Tree Lights: If one light goes out and the rest go dark, they are connected in series.
• Using Batteries: Connecting 8 batteries in different configurations to achieve desired voltage and current.

Additional Information

• Power Calculations: Wattage is calculated as current multiplied by voltage (W = IV).
• Magnetism: The transformation ratio of a transformer is the ratio of primary to secondary turns (e.g., 240:40 is a 6:1 ratio).
• Current-Induced Heat: In circuits, heat is generated when current overcomes resistance.
• Zener Diodes: Allow current flow in the reverse direction when breakdown voltage is exceeded.