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General - Electrical principles
Electrical principles groups the G5 section questions for focused review and easier weak-point tracking.
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Read the condition in the stem before comparing key terms in the options.
Study rules, calculations, and equipment questions as separate patterns.
After this topic, return to the full pool for mixed practice.
Topic Study Guide
This topic covers G5 Electrical Principles, focusing on AC characteristics (impedance, reactance, admittance), resonant circuits, and calculations for power, RMS, and peak voltages. Mastering these concepts is essential for understanding antennas and RF circuits.
High-Yield Checks
- Reactance vs. Frequency: Inductor reactance increases with frequency, while capacitor reactance decreases with frequency.
- Voltage conversions: RMS = Peak × 0.707; Peak-to-Peak = Peak × 2.
- LC circuit resonance: At resonance, inductive and capacitive reactances cancel out, making series impedance very low.
- Core power formulas: P = V×I, P = V²/R, and P = I²×R. Be prepared to use these interchangeably based on given values.
Trap Patterns
- Using the Peak-to-Peak voltage directly in power formulas instead of first halving it and converting it to RMS.
- Mixing up electrical symbols and terms: confusing Reactance (X) with Impedance (Z), or forgetting that Admittance is the inverse of Impedance.
- Forgetting to convert milliamperes (mA) to amperes (A) before squaring the current in the P = I²×R formula.
Review Steps
- Step 1: Memorize the definitions, symbols, and units (Ohms) for Impedance (Z), Reactance (X), and Admittance (Y).
- Step 2: Compare and memorize the AC characteristics of inductors and capacitors, focusing on their opposite reactions to frequency changes.
- Step 3: Practice the voltage conversion chain (Peak-to-Peak -> Peak -> RMS) on paper to ensure you don't mix up the 0.707 and 1.414 multipliers.
- Step 4: Tackle calculation questions in a batch. Write down the formula, plug in the values, check units (e.g., mA to A), and then calculate.
Quick Checks
- What happens to a capacitor's reactance as the AC frequency increases?
- How do you calculate the RMS voltage from a given Peak-to-Peak voltage?
- What happens to the inductive and capacitive reactance in a series LC circuit at resonance?
- What is the term for the inverse of impedance?
Questions in This Topic
Choose Practice ModeG5A01What happens when inductive and capacitive reactance are equal in a series LC circuit?G5A02What is reactance?G5A03Which of the following is opposition to the flow of alternating current in an inductor?G5A04Which of the following is opposition to the flow of alternating current in a capacitor?G5A05How does an inductor react to AC?G5A06How does a capacitor react to AC?G5A07What is the term for the inverse of impedance?G5A08What is impedance?G5A09What unit is used to measure reactance?G5A10Which of the following devices can be used for impedance matching at radio frequencies?G5A11What letter is used to represent reactance?G5A12What occurs in an LC circuit at resonance?G5B01What dB change represents a factor of two increase or decrease in power?G5B02How does the total current relate to the individual currents in a circuit of parallel resistors?G5B03How many watts of electrical power are consumed if 400 VDC is supplied to an 800-ohm load?G5B04How many watts of electrical power are consumed by a 12 VDC light bulb that draws 0.2 amperes?G5B05How many watts are consumed when a current of 7.0 milliamperes flows through a 1,250-ohm resistance?G5B06What is the PEP produced by 200 volts peak-to-peak across a 50-ohm dummy load?G5B07What value of an AC signal produces the same power dissipation in a resistor as a DC voltage of the same value?G5B08What is the peak-to-peak voltage of a sine wave with an RMS voltage of 120 volts?G5B09What is the RMS voltage of a sine wave with a value of 17 volts peak?G5B10What percentage of power loss is equivalent to a loss of 1 dB?G5B11What is the ratio of PEP to average power for an unmodulated carrier?G5B12What is the RMS voltage across a 50-ohm dummy load dissipating 1200 watts?G5B13What is the output PEP of an unmodulated carrier if the average power is 1060 watts?G5B14What is the output PEP of 500 volts peak-to-peak across a 50-ohm load?G5C01What causes a voltage to appear across the secondary winding of a transformer when an AC voltage source is connected across its primary winding?G5C02What is the output voltage if an input signal is applied to the secondary winding of a 4:1 voltage step-down transformer instead of the primary winding?G5C03What is the total resistance of a 10-, a 20-, and a 50-ohm resistor connected in parallel?G5C04What is the approximate total resistance of a 100- and a 200-ohm resistor in parallel?G5C05Why is the primary winding wire of a voltage step-up transformer usually a larger size than that of the secondary winding?G5C06What is the voltage output of a transformer with a 500-turn primary and a 1500-turn secondary when 120 VAC is applied to the primary?G5C07What transformer turns ratio matches an antenna’s 600-ohm feed point impedance to a 50-ohm coaxial cable?G5C08What is the equivalent capacitance of two 5.0-nanofarad capacitors and one 750-picofarad capacitor connected in parallel?G5C09What is the capacitance of three 100-microfarad capacitors connected in series?G5C10What is the inductance of three 10-millihenry inductors connected in parallel?G5C11What is the inductance of a circuit with a 20-millihenry inductor connected in series with a 50-millihenry inductor?G5C12What is the capacitance of a 20-microfarad capacitor connected in series with a 50-microfarad capacitor?G5C13Which of the following components should be added to a capacitor to increase the capacitance?G5C14Which of the following components should be added to an inductor to increase the inductance?