| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.27 |
| Score | 0% | 65% |
Which of the following is not a characteristic of a step-up transformer?
the primary voltage is higher than the secondary voltage |
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the secondary voltage is higher than the primary voltage |
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has more turns in the secondary winding than in the primary winding |
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increases voltage |
As their names indicate, a step-up transformer is used to step up or increase voltage and a step-down transformer is used to step down or decrease voltage. In a step-up transformer, the secondary voltage is higher than the primary voltage and it has more turns in the secondary winding than in the primary winding.
The conversion of alternating current (AC) into direct current (DC) is called:
inductance |
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capacitance |
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reactance |
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rectification |
A diode allows current to pass easily in one direction and blocks current in the other direction. Diodes are commonly used for rectification which is the conversion of alternating current (AC) into direct current (DC). Because a diode only allows current flow in one direction, it will pass either the upper or lower half of AC waves (half-wave rectification) creating pulsating DC. Multiple diodes can be connected together to utilize both halves of the AC signal in full-wave rectification.
A capacitor is often used for which of the following purposes?
to maintain power in a circuit when the primary power source is disconnected |
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to convert alternating current into direct current |
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to allow a small amount of current to control a large amount of current |
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as a primary power source |
Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.
The valence shell of a conductor is how full of electrons?
full |
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more than half full |
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half full |
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less than half full |
Conductors are elements that allow electrons to flow freely. Their valence shell is less than half full of electrons that are able to move easily from one atom to another.
| 520 V | |
| 780 V | |
| 523 V | |
| 173.33 V |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
V = \( I \times R \) = \( 6.5 \times 80 \) = 520 V