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General - Practical circuits
Practical circuits groups the G7 section questions for focused review and easier weak-point tracking.
38
Questions
9
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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 practical circuits commonly used in amateur radio, including power supplies (rectification and filtering), amplifier classes and efficiency, basic digital logic, and oscillator principles. It also requires identifying schematic symbols for common electronic components.
High-Yield Checks
- Power supply basics: Half-wave (1 diode, 180 degrees), Full-wave (2 diodes + center-tapped, 360 degrees). Bleeder resistors discharge capacitors after power is removed.
- Amplifier classes: Class A conducts 100% of the time (most linear, least efficient); Class C has the highest efficiency.
- Schematic symbols: Memorize the visual differences between NPN/PNP transistors, FETs, Zener diodes, and various transformer/inductor cores.
- Digital logic & Oscillators: AND gates require both inputs high; a 3-bit counter has 8 states (2^3); LC oscillator frequency is determined by the L and C in the tank circuit.
Trap Patterns
- Confusing full-wave and full-wave bridge rectifiers. A full-wave rectifier uses 2 diodes with a center-tapped transformer, while a bridge uses 4 diodes.
- Misunderstanding amplifier efficiency calculation. It is RF output power divided by DC input power, not RF input.
- Assuming switchmode power supplies use fewer components. They actually use smaller components due to high-frequency operation, but the circuitry is more complex.
Review Steps
- Review Figure G7-1 and practice identifying each component symbol until you can name them instantly.
- Group power supply questions together: trace the path from AC input, through the rectifier, filter network (L and C), to the bleeder resistor.
- Compare amplifier classes (A, B, AB, C) side-by-side, focusing on conduction angle (percentage of time conducting) and efficiency.
- Memorize the basic definitions of digital circuits like AND gates, shift registers, and binary counters.
Quick Checks
- Can you explain the difference between a full-wave and a full-wave bridge rectifier?
- Do you know which amplifier class conducts 100% of the time versus which is the most efficient?
- Can you identify the symbols for a Zener diode, FET, and NPN transistor without looking at the labels?
- How do you calculate the number of states in a binary counter based on its bits?
Questions in This Topic
Choose Practice ModeG7A01What is the function of a power supply bleeder resistor?G7A02Which of the following components are used in a power supply filter network?G7A03Which type of rectifier circuit uses two diodes and a center-tapped transformer?G7A04What is characteristic of a half-wave rectifier in a power supply?G7A05What portion of the AC cycle is converted to DC by a half-wave rectifier?G7A06What portion of the AC cycle is converted to DC by a full-wave rectifier?G7A07What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?G7A08Which of the following is characteristic of a switchmode power supply as compared to a linear power supply?G7A09Which symbol in figure G7-1 represents a field effect transistor?G7A10Which symbol in figure G7-1 represents a Zener diode?G7A11Which symbol in figure G7-1 represents an NPN junction transistor?G7A12Which symbol in Figure G7-1 represents a solid core transformer?G7A13Which symbol in Figure G7-1 represents a tapped inductor?G7B01What is the purpose of neutralizing an amplifier?G7B02Which of these classes of amplifiers has the highest efficiency?G7B03Which of the following describes the function of a two-input AND gate?G7B04In a Class A amplifier, what percentage of the time does the amplifying device conduct?G7B05How many states does a 3-bit binary counter have?G7B06What is a shift register?G7B07Which of the following are basic components of a sine wave oscillator?G7B08How is the efficiency of an RF power amplifier determined?G7B09What determines the frequency of an LC oscillator?G7B10Which of the following describes a linear amplifier?G7B11For which of the following modes is a Class C power stage appropriate for amplifying a modulated signal?G7C01What circuit is used to select one of the sidebands from a balanced modulator?G7C02What output is produced by a balanced modulator?G7C03What is one reason to use an impedance matching transformer at a transmitter output?G7C04How is a product detector used?G7C05Which of the following is characteristic of a direct digital synthesizer (DDS)?G7C06Which of the following is an advantage of a digital signal processing (DSP) filter compared to an analog filter?G7C07What term specifies a filter’s attenuation inside its passband?G7C08Which parameter affects receiver sensitivity?G7C09What is the phase difference between the I and Q RF signals that software-defined radio (SDR) equipment uses for modulation and demodulation?G7C10What is an advantage of using I-Q modulation with software-defined radios (SDRs)?G7C11Which of these functions is performed by software in a software-defined radio (SDR)?G7C12What is the frequency above which a low-pass filter’s output power is less than half the input power?G7C13What term specifies a filter’s maximum ability to reject signals outside its passband?G7C14The bandwidth of a band-pass filter is measured between what two frequencies?