Question 1

Light-emitting diodes can be tested in a manner similar to that of testing a junction diode.

Accepted Answer

Light-emitting diodes (LEDs) can be tested using a similar method to that of testing a junction diode, as both types of diodes have a forward voltage drop and allow current to flow in only one direction. However, the voltage and current ratings may be different for LEDs, and they may emit light when forward biased.

Question 2

When used in a circuit, the LED generally operates with a current of about 20 mA or less.

Accepted Answer

LEDs typically operate with a current of around 20 mA or less to prevent damaging the LED and to ensure efficient operation.

Question 3

Common anode displays are energized by connecting the appropriate cathode lead to a ____ voltage.&#10;A) negative&#10;B) more negative&#10;C) more positive&#10;D) positive

Accepted Answer

Common anode displays are energized by connecting the appropriate cathode lead to a more negative voltage relative to the anode, which is typically connected to a positive voltage. This allows current to flow through the LED or segment, illuminating it.

Question 4

The basic light-emitting diode is formed by joining gallium arsenide (GaAs) or ____ with some other material.&#10;A) gallium arsenide phosphide (GaAsP)&#10;B) zinc selenide (ZnSe)&#10;C) silicon carbide (SiC)&#10;D) gallium phosphide (GaP)

Accepted Answer

The basic light-emitting diode is formed by joining gallium arsenide (GaAs) or gallium phosphide (GaP) with some other material. Among the given options, only option D is a possible material for LED fabrication.

Question 5

Light-emitting diodes (LEDs) are used as stop lights in many types of equipment.

Accepted Answer

The answer of Light-emitting diodes (LEDs) are used as stop...

Question 6

The case of most LEDs will have a flat side that is located closer to the anode lead.

Accepted Answer

The flat side of most LEDs is actually located closer to the cathode lead, not the anode, to help identify the polarity.

Question 7

An advantage of photodiodes is that they can operate ____.&#10;A) at very high frequencies&#10;B) at small intervals&#10;C) with no light&#10;D) at very low frequencies

Accepted Answer

Photodiodes have fast response times and can operate at high frequencies, making them suitable for applications such as fiber optic communication and high-speed data transfer.

Question 8

Photodiodes can be used as photovoltaic devices.

Accepted Answer

Photodiodes can be used as photovoltaic devices, meaning they can generate electrical power when exposed to light.

Question 9

When light-emitting diodes are used in applications where they are intended to block any amount of reverse voltage, they are connected in series with a ____.&#10;A) photodiode&#10;B) photovoltaic device&#10;C) junction diode&#10;D) photoconductive device

Accepted Answer

When light-emitting diodes are used in applications where they need to block any reverse voltage, they are connected in series with a junction diode to utilize the diode's ability to block reverse current flow.

Question 10

For most practical purposes, the ____ of a photoconductive device is generally considered to be zero.&#10;A) dark current&#10;B) light current&#10;C) voltage drop&#10;D) resistance

Accepted Answer

Dark current refers to the current that flows through a photoconductive device in the absence of light. It is considered to be the "baseline" current that is present in the device, and therefore its value is generally considered to be zero for practical purposes.

Deck 51: Light-Emitting Diodes Leds and Photodiodes