Eletrônica Geral - Avaliação 1

Semicondutores são materiais que possuem uma condutividade elétrica intermediária entre condutores e isolantes. Os semicondutores mais utilizados na indústria eletrônica são feitos a partir de cristais de silício e germânio. Esses materiais possuem uma estrutura cristalina que permite que elétrons se movam facilmente dentro deles, mas não de forma tão livre quanto em condutores. O silício e o germânio possuem características que os tornam ideais para a fabricação de dispositivos eletrônicos, como transistores e circuitos integrados.

Dopagem é o processo de adicionar impurezas no cristal de um semicondutor para alterar suas propriedades elétricas. A purificação do cristal, por outro lado, é um processo separado que visa remover impurezas e obter um cristal de alta qualidade com uma estrutura uniforme. Portanto, é incorreto dizer que a dopagem é a purificação do cristal.

The correct answer is "Diretamente polarizado e após romper a barreira de potencial." This means that a diode only conducts when it is forward biased (directamente polarizado) and the voltage applied across it is greater than the barrier potential (após romper a barreira de potencial). In other words, current can only flow through a diode when it is connected in the correct orientation and a sufficient voltage is applied.

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A diode rectifier has one PN junction. A PN junction is formed when a P-type semiconductor material is joined with an N-type semiconductor material. In a diode rectifier, this PN junction allows current to flow in one direction while blocking it in the opposite direction, enabling the conversion of AC (alternating current) to DC (direct current). Therefore, a diode rectifier only requires one PN junction to perform its function.

The correct answer is A Apagada - B Acesa - C Apagada - D Apagada. This means that the first bulb is off, the second bulb is on, the third bulb is off, and the fourth bulb is off.

The correct answer is A Apagada - B Apagada - C Apagada - D Apagada. This means that all the bulbs are turned off.

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By adding pentavalent impurities to the silicon or germanium crystal, we can obtain an N-type semiconductor.

Based on the given options, it can be inferred that only option C is indicating that the light bulb C is turned on while the others are turned off. Therefore, the correct answer is A Apagada- B Apagada - C Acesa - D Apagada.

The correct answer is "Conduzir a corrente elétrica apenas em uma direção." A rectifier diode is designed to allow the flow of current in only one direction. It acts as a one-way valve for electric current, allowing it to pass through in the forward direction while blocking it in the reverse direction. This characteristic makes rectifier diodes essential in converting alternating current (AC) to direct current (DC) in power supplies and other electronic circuits.

By adding trivalent impurities to the silicon or germanium crystal, we can obtain a P-type semiconductor.

The correct answer is "Converter corrente pulsante em contínua." This means that the function of filtrar is to convert pulsating current into direct current.

The correct answer is "Polarização direta e inversa." This means that the base-emitter junction is forward-biased (polarização direta) while the base-collector junction is reverse-biased (polarização inversa). This type of biasing allows the transistor to operate in its active region and amplify signals effectively.

Atoms with 1, 2, and 3 electrons in their outermost shell are considered good conductors of electricity. This is because these atoms have fewer electrons in their outer shell, making it easier for them to lose or gain electrons and form ions. These ions can then move freely in a conductive material, allowing the flow of electric current. Conversely, atoms with a full outer shell (8 electrons) or close to a full outer shell (5, 6, or 7 electrons) are less likely to lose or gain electrons, making them poor conductors of electricity.

The given answer states that IT is equal to 4.7mA. This is because IT is calculated by summing the currents I1 and I2, and the values of I1 and I2 are not provided. Therefore, based on the given information, we can only conclude that IT is equal to 4.7mA.

Diodos de silício conduzem após 0,7V e diodos de germânio conduzem após 0,3V.

Retificar é o processo de converter corrente alternada em corrente pulsante. Durante a retificação, a corrente que flui em uma direção é permitida a passar enquanto a corrente que flui na direção oposta é bloqueada. Isso resulta em uma corrente que flutua entre zero e um valor máximo, criando uma forma de onda pulsante. Portanto, a resposta correta é "Converter corrente alternada em pulsante".

Ligar o positivo da fonte com o anodo e negativo com catodo é a forma correta de polarizar um diodo diretamente. Portanto, a resposta que afirma que "A e C estão incorretas" é a resposta correta.

When VCE = 0V in the amplifier circuit, it means that the voltage between the collector and the emitter is zero. This indicates that the transistor is in the cutoff region, where it is not allowing any current to flow from the collector to the emitter. Therefore, the collector current is at its maximum value, as no current is being drawn away from it. The voltage across the collector resistor (RC) is also zero, as no current is passing through it. The base current is also zero, as the transistor is not conducting any current.

In a half-wave rectifier, the load receives current in both the positive and negative half-cycles of the input waveform. This means that during the positive half-cycle, the load receives current when the input voltage is positive, and during the negative half-cycle, the load receives current when the input voltage is negative. Therefore, the load receives current in both semicircles of the input waveform.

The given question provides the values of collector current (IC) and emitter current (IE) for a bipolar transistor. To find the value of "B" (also known as the current gain or beta), we can use the formula B = IC / IE. Plugging in the given values, we get B = 20.0 mA / 20.1 mA, which simplifies to B = 0.995. Rounding this to the nearest whole number, we get B = 1. Therefore, the correct answer is B = 1.