CA_ADV
Advanced - Measurements and troubleshooting
Measurements and troubleshooting follows the A-004 section of the Canadian question bank.
44
Questions
6
Sibling Topics
- Pool
- Advanced
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- 44
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- Measurements and troubleshooting
- Region
- CA
Review by section order to build the topic framework first.
For regulatory and safety questions, prefer compliant and conservative actions.
For calculations, check units, multipliers, and approximations.
Topic Study Guide
This topic covers section A-004 of the Canadian Advanced exam, focusing on the fundamental principles of power supply circuits, including rectifier configurations, filter network characteristics, and linear voltage regulator mechanisms.
High-Yield Checks
- Bridge vs. Centre-tap: For the same secondary voltage, a bridge rectifier has the highest average output voltage (double that of a full-wave centre-tap design).
- Peak Inverse Voltage (PIV): The PIV of a full-wave centre-tap supply is 2.8 times the RMS voltage. The two critical diode ratings are PIV and average forward current.
- Ripple Frequency: On a 60 Hz supply, a half-wave rectifier produces a 60 Hz ripple, while an unfiltered full-wave rectifier outputs pulses at 120 Hz (twice the input frequency).
- Filtering & Regulation: Choke-input filters provide the best regulation. Bleeder resistors improve regulation by maintaining a minimum current draw.
- Three-terminal Regulators: These contain a voltage reference (typically a Zener diode), error amplifier, sensing resistors/transistors, and a pass element.
Trap Patterns
- Assuming all power supplies have a 120 Hz ripple, forgetting that a half-wave rectifier's ripple frequency matches the input AC frequency (60 Hz).
- Using the standard 1.4 multiplier for PIV in a centre-tap rectifier, forgetting that the reverse-biased diode sees the full end-to-end transformer voltage (2.8 times RMS).
- Confusing capacitor-input and choke-input filters. Capacitor inputs give higher initial voltage, but choke inputs provide much better regulation under varying loads.
- Confusing linear regulators with switching regulators by assuming linear regulators use duty-cycle switching, whereas they actually vary conduction proportionally.
Review Steps
- Step 1: Compare the three rectifier topologies (half-wave, full-wave centre-tap, bridge), memorizing their differences in output voltage multipliers, ripple frequencies, and PIV requirements.
- Step 2: Analyze filter circuits. Understand the role of the choke in series resonance and improving regulation, as well as the stabilizing function of bleeder resistors.
- Step 3: Break down linear regulator structures. Memorize the four internal components of a three-terminal regulator and recognize the Zener diode's role as the reference voltage.
- Step 4: Differentiate between static regulation (long-term load changes) and dynamic regulation (improved by increasing output capacitance), and identify the optimal connection point for the sampling network.
Quick Checks
- What is the PIV multiplier for a full-wave centre-tap power supply compared to the RMS voltage?
- What is the ripple frequency of a half-wave power supply connected to a normal 60 Hz household circuit?
- Which filter circuit provides the best regulation under similar load conditions?
- What component is typically used to provide a stable reference voltage inside a three-terminal regulator?
Questions in This Topic
Choose Practice ModeA-004-001-001For the same transformer secondary voltage, which rectifier has the highest average output voltage?A-004-001-002In a half-wave power supply with a capacitor input filter and a load drawing little or no current, the peak inverse voltage (PIV) across the diode can reach _____ times the RMS voltage.A-004-001-003In a full-wave centre-tap power supply, regardless of load conditions, the peak inverse voltage (PIV) will be _____ times the RMS voltage:A-004-001-004A full-wave bridge rectifier circuit makes use of both halves of the AC cycle, but unlike the full-wave centre-tap rectifier circuit it does not require:A-004-001-005For a given transformer the maximum output voltage available from a full-wave bridge rectifier circuit will be:A-004-001-006The ripple frequency produced by a full-wave power supply connected to a normal household circuit is:A-004-001-007The ripple frequency produced by a half-wave power supply connected to a normal household circuit is:A-004-001-008Full-wave voltage doublers:A-004-001-009What are the two major ratings that must not be exceeded for silicon-diode rectifiers used in power-supply circuits?A-004-001-010In a high voltage power supply, why should a resistor and capacitor be wired in parallel with the power-supply rectifier diodes?A-004-001-011What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?A-004-002-001Filter chokes are rated according to:A-004-002-002Which of the following circuits gives the best regulation, under similar load conditions?A-004-002-003The advantage of the capacitor input filter over the choke input filter is:A-004-002-004With a normal load, the choke input filter will give the:A-004-002-005There are two types of filters in general use in a power supply. They are called:A-004-002-006The main function of the bleeder resistor in a power supply is to provide a discharge path for the capacitor in the power supply. But it may also be used for a secondary function, which is to:A-004-002-007In a power supply, series chokes will:A-004-002-008When using a choke input filter, a minimum current should be drawn all the time when the device is switched on. This can be accomplished by:A-004-002-009In the design of a power supply, the designer must be careful of resonance effects because the ripple voltage could build up to a high value. The components that must be carefully selected are:A-004-002-010Excessive rectifier peak current and abnormally high peak inverse voltages can be caused in a power supply by the filter forming a:A-004-002-011In a properly designed choke input filter power supply, the no-load voltage across the filter capacitor will be about nine-tenths of the AC RMS voltage yet it is advisable to use capacitors rated at the peak transformer voltage. Why is this large safety margin suggested?A-004-003-001What is one characteristic of a linear electronic voltage regulator?A-004-003-002What is one characteristic of a switching voltage regulator?A-004-003-003What device is typically used as a stable reference voltage in a linear voltage regulator?A-004-003-004What type of linear regulator is used in applications requiring efficient utilization of the primary power source?A-004-003-005What type of linear voltage regulator is used in applications requiring a constant load on the unregulated voltage source?A-004-003-006How is remote sensing accomplished in a linear voltage regulator?A-004-003-007What is a three-terminal regulator?A-004-003-008In addition to an input voltage range what are the important characteristics of a three-terminal regulator?A-004-003-009What type of voltage regulator contains a voltage reference, error amplifier, sensing resistors and transistors, and a pass element in one package?A-004-003-010When extremely low ripple is required, or when the voltage supplied to the load must remain constant under conditions of large fluctuations of current and line voltage, a closed-loop amplifier is used to regulate the power supply. There are two main categories of electronic regulators. They are:A-004-003-011A modern type of regulator, which features a reference, high-gain amplifier, temperature-compensated voltage sensing resistors and transistors as well as a pass element is commonly referred to as a:A-004-004-001In a series-regulated power supply, the power dissipation of the pass transistor is:A-004-004-002In any regulated power supply, the output is cleanest and the regulation is best:A-004-004-003When discussing a power supply the_______ resistance is equal to the output voltage divided by the total current drawn, including the current drawn by the bleeder resistor:A-004-004-004The regulation of long-term changes in the load resistance of a power supply is called:A-004-004-005The regulation of short-term changes in the load resistance of a power supply is called:A-004-004-006The dynamic regulation of a power supply is improved by increasing the value of:A-004-004-007The output capacitor, in a power supply filter used to provide power for an SSB or CW transmitter, will give better dynamic regulation if:A-004-004-008In a regulated power supply, four diodes connected together in a BRIDGE act as:A-004-004-009In a regulated power supply, components that conduct alternating current at the input before the transformer and direct current before the output are:A-004-004-010In a regulated power supply, the output of the electrolytic filter capacitor is connected to the:A-004-004-011In a regulated power supply, a diode connected across the input and output terminals of a regulator is used to: