| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.17 |
| Score | 0% | 63% |
The formula specifying Ohm's law is which of the following?
V = I2R |
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V = IR |
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\(V = {R \over I}\) |
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\(V = {I \over R}\) |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
This circuit component symbol represents a(n):
capacitor |
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transformer |
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DC source |
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AC source |
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.
Which of the following will increase the magnetic field produced by the electric current in a wire?
wind the wire into a coil |
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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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construct the wire from conductive material |
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 is the primary difference between a rectifier and an inverter?
a rectifier converts an AC input to DC while an inverter converts a DC input to AC |
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a rectifier converts a DC input to AC while an inverter converts an AC input to DC |
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a rectifier strips out the AC portion of electricity while an inverter strips out the DC portion |
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a rectifier strips out the DC portion of electricity while an inverter strips out the AC portion |
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 a step-up transformer?
the secondary voltage is higher than the primary voltage |
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the primary voltage is higher than the secondary voltage |
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increases 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.