| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.38 |
| Score | 0% | 68% |
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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increases 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 |
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.
Which of the following is not an advantage of semiconductors over conductors?
a semiconductor's conductivity can be varied under an external electrical field |
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a semiconductor exhibits increased conductivity with increased temperatures |
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a semiconductor conducts current better than a conductor |
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materials to produce semiconductors are cheap and abundant |
A semiconductor is a material that has a limited ability to conduct electrical current with conductivity between that of an insulator and that of a conductor. Silicon, a cheap and abundant material, is the most used semiconductor material although other materials are used in the electronics components made from semiconductors. The primary advantages of a semiconductor over a conductor is that the conductivity of a semiconductor can be varied under an external electrical field giving engineers precise control over complex circuits and, unlike conductors like metals, a semiconductor's conductivity increases with increased temperatures.
A capacitor to an electronic circuit is like a _______________ to a house?
gate |
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driveway |
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safe |
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storage shed |
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.
Resistance is measured in:
coulombs |
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volts |
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ohms |
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amperes |
Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional.
The ohm is a unit of measurement for:
resistance |
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capacitance |
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energy |
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power |
Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional.