| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.12 |
| Score | 0% | 62% |
Which of the following is not an advantage of semiconductors over conductors?
a semiconductor conducts current better than a conductor |
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a semiconductor exhibits increased conductivity with increased temperatures |
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materials to produce semiconductors are cheap and abundant |
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a semiconductor's conductivity can be varied under an external electrical field |
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.
The most common circuit configuration is:
parallel |
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series |
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series-parallel |
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household |
Circuits are not limited to only series or only parallel configurations. Most circuits contain a mix of series and parallel segments. A good example is a household circuit breaker. Electrical outlets in each section of the house are wired in parallel with the circuit breaker for that section wired in series making it easy to cut off electricity to the parallel parts of the circuit when needed.
The farad is a unit of measurement for:
power |
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inductance |
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energy |
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capacitance |
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.
Direct current flows from the __________ terminal of the voltage source to the __________ terminal.
positive, positive |
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negative, positive |
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positive, negative |
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negative, negative |
Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery.
| 7.7 A | |
| 3.5 A | |
| 6.3 A | |
| 7 A |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
Solved for current, I = \( \frac{V}{R} \) = \( \frac{700}{100} \) = 7 A