| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.04 |
| Score | 0% | 61% |
The joule is a unit of measurement for:
capacitance |
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power |
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resistance |
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energy |
The joule is a unit of measurement for energy.
This circuit component symbol represents a(n):
inductor |
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diode |
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transistor |
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capacitor |
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.
Which of the following is not a characteristic of direct current?
cannot easily travel distances without power loss |
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used to power your cell phone |
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electrons flow in only one consistent direction |
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an example power source is a generator |
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 DC is a battery. In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances.
Which of the following will increase the magnetic field produced by the electric current in a wire?
construct the wire from conductive material |
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wrap the wire around a ceramic core |
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construct the wire from insulative material |
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wind the wire into a coil |
A moving electric current produces a magnetic field proportional to the amount of current flow. This magnetic field can be made stronger by winding the wire into a coil and further enhanced if done around an iron containing (ferrous) core.
What kind of diode allows current to flow in the opposite direction once a certain voltage threshold is reached?
light emitting diode |
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standard diode |
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zener diode |
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v-type diode |
A diode allows current to pass easily in one direction and blocks current in the other direction. A zener diode is a diode which allows current to flow in one direction as normal and will also allow current flow in the reverse direction when the voltage is above a certain value. This value is called the breakdown voltage.