95 lines
4.9 KiB
Markdown
95 lines
4.9 KiB
Markdown
E7D Power supplies and voltage regulators; solar array charge controllers
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- [[E7D01]] (D)
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How does a linear electronic voltage regulator work? #card
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- [[A.]] It has a ramp voltage as its output
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- [[B.]] It eliminates the need for a pass transistor
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- [[C.]] The control element duty cycle is proportional to the line or load conditions
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- [[D.]] The conduction of a control element is varied to maintain a constant output voltage
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- [[E7D02]] (B)
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How does a switchmode voltage regulator work? #card
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- [[A.]] By alternating the output between positive and negative voltages
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- [[B.]] By varying the duty cycle of pulses input to a filter
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- [[C.]] By varying the conductivity of a pass element
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- [[D.]] By switching between two Zener diode reference voltages
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- [[E7D03]] (A)
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What device is used as a stable voltage reference? #card
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- [[A.]] A Zener diode
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- [[B.]] A digital-to-analog converter
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- [[C.]] An SCR
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- [[D.]] An analog-to-digital converter
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- [[E7D04]] (B)
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Which of the following describes a three-terminal voltage regulator? #card
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- [[A.]] A series current source
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- [[B.]] A series regulator
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- [[C.]] A shunt regulator
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- [[D.]] A shunt current source
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- [[E7D05]] (D)
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Which of the following types of linear voltage regulator operates by loading the unregulated voltage source? #card
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- [[A.]] A constant current source
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- [[B.]] A series regulator
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- [[C.]] A shunt current source
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- [[D.]] A shunt regulator
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- [[E7D06]] (C)
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What is the purpose of Q1 in the circuit shown in Figure [[E7-2]]? #card
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- [[A.]] It provides negative feedback to improve regulation
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- [[B.]] It provides a constant load for the voltage source
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- [[C.]] It controls the current to keep the output voltage constant
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- [[D.]] It provides regulation by switching or “chopping” the input DC voltage
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- [[E7D07]] (A)
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What is the purpose of C2 in the circuit shown in Figure [[E7-2]]? #card
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- [[A.]] It bypasses rectifier output ripple around D1
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- [[B.]] It is a brute force filter for the output
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- [[C.]] To prevent self-oscillation
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- [[D.]] To provide fixed DC bias for Q1
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- [[E7D08]] (C)
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What type of circuit is shown in Figure [[E7-2]]? #card
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- [[A.]] Switching voltage regulator
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- [[B.]] Common emitter amplifier
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- [[C.]] Linear voltage regulator
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- [[D.]] Common base amplifier
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- [[E7D09]] (C)
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How is battery operating time calculated? #card
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- [[A.]] Average current divided by capacity in amp-hours
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- [[B.]] Average current divided by internal resistance
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- [[C.]] Capacity in amp-hours divided by average current
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- [[D.]] Internal resistance divided by average current
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- [[E7D10]] (C)
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Why is a switching type power supply less expensive and lighter than an equivalent linear power supply? #card
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- [[A.]] The inverter design does not require an output filter circuit
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- [[B.]] The control circuitry uses less current, therefore smaller heat sinks are required
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- [[C.]] The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
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- [[D.]] It recovers power from the unused portion of the AC cycle, thus using fewer components
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- [[E7D11]] (D)
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What is the purpose of an inverter connected to a solar panel output? #card
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- [[A.]] Reduce AC ripple on the output
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- [[B.]] Maintain voltage with varying illumination levels
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- [[C.]] Prevent discharge when panel is not illuminated
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- [[D.]] Convert the panel’s output from DC to AC
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- [[E7D12]] (C)
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What is the dropout voltage of a linear voltage regulator? #card
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- [[A.]] Minimum input voltage for rated power dissipation
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- [[B.]] Maximum output voltage drop when the input voltage is varied over its specified range
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- [[C.]] Minimum input-to-output voltage required to maintain regulation
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- [[D.]] Maximum that the output voltage may decrease at rated load
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- [[E7D13]] (C)
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Which of the following calculates power dissipated by a series linear voltage regulator? #card
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- [[A.]] Input voltage multiplied by input current
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- [[B.]] Input voltage divided by output current
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- [[C.]] Voltage difference from input to output multiplied by output current
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- [[D.]] Output voltage multiplied by output current
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- [[E7D14]] (D)
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What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series? #card
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- [[A.]] Equalize the voltage across each capacitor
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- [[B.]] Discharge the capacitors when voltage is removed
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- [[C.]] Provide a minimum load on the supply
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- [[D.]] All these choices are correct
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- [[E7D15]] (D)
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What is the purpose of a step-start circuit in a high-voltage power supply? #card
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- [[A.]] To provide a dual-voltage output for reduced power applications
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- [[B.]] To compensate for variations of the incoming line voltage
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- [[C.]] To prevent arcing across the input power switch or relay contacts
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- [[D.]] To allow the filter capacitors to charge gradually |