| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.24 |
| Score | 0% | 65% |
Which of the following statements about a capacitor is false?
it is safe to touch a capacitor with your hands as long as it is small |
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to discharge a capacitor safely, use a high-wattage resistor comparable to the capacitance of the capacitor |
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a capacitor remains charged even after the input voltage is removed |
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you should always discharge any capacitors before working on an electronic circuit |
The purpose of a capacitor is to retain electric charge and it will do so even after its input voltage is removed. After the input voltage is removed, the capacitor will slowly discharge but, depending on the size and characteristics of the capacitor, discharging could take from a few minutes to a few years. So, it's never safe to touch a capacitor with your hands and you should make sure to discharge any capacitors in a circuit before working on it using an appropriately high-wattage resistor or a capacitor discharge tool.
Electromotive force is another name for:
power |
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voltage |
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current |
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energy |
Voltage (V) is the electrical potential difference between two points. Electrons will flow as current from areas of high potential (concentration of electrons) to areas of low potential. Voltage and current are directly proportional in that the higher the voltage applied to a conductor the higher the current that will result.
Which of the following is a characteristic of batteries connected in series?
total voltage equals the sum of the individual battery voltages |
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the positive terminal of one battery is connected to the positive terminal of the next |
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two connections are made between each adjacent battery |
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total voltage equals the average of the individual battery voltages |
You can multiply the voltage or the current supplied by individual batteries by connecting them together either in series or in parallel. The characteristics of batteries connected in series are that total voltage equals the sum of the individual battery voltages, total current equals the average of the individual battery currents, the positive terminal of one battery is connected to the negative terminal of the next, and one connection is made between each adjacent battery.
Which of the following allows current to pass easily in one direction and blocks current in the other direction?
inductor |
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capacitor |
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diode |
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resistor |
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.
This circuit component symbol represents a(n):
transistor |
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DC source |
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AC source |
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transformer |
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.