| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.34 |
| Score | 0% | 67% |
In metals, increasing the temperature typically _____________ conductivity.
does nothing to |
|
decreases |
|
eliminates |
|
increases |
All conductors have resistance and the amount of resistance varies with the element. Metals exhibit increased resistance (and, therefore, lower conductivity) as their temperature increases.
Which of the following statements about a capacitor is false?
to discharge a capacitor safely, use a high-wattage resistor comparable to the capacitance of the capacitor |
|
you should always discharge any capacitors before working on an electronic circuit |
|
a capacitor remains charged even after the input voltage is removed |
|
it is safe to touch a capacitor with your hands as long as it is small |
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.
Which of the following statements about electrical resistance is true?
the more resistive the conductor is the slower electron flow will be |
|
the more resistive the conductor is the faster electron flow will be |
|
electrically conductive materials have no resistive properties |
|
the less resistive the conductor is the slower electron flow will be |
Resistance is opposition to the flow of current. As resistance increases, current decreases as resistance and current are inversely proportional.
The farad is a unit of measurement for:
capacitance |
|
energy |
|
inductance |
|
power |
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.
This circuit component symbol represents a(n):
transistor |
|
diode |
|
capacitor |
|
inductor |
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.