Special Purpose Diodes

To use Zener diode of maximum power rating $1.0$ W as a $4.0$ V stabilized power supply, the maximum current flowing through Zener diode will

When the Zener diode is used as a voltage regulator, it is connected in

Choose the correct statement about Zener diode:

A LED emits visible light when its

Which one of the following statements is 'WRONG' regarding LED?

Which of the following statement is NOT correct in the case of LED?

(A) It is a heavily doped p-n junction diode.

(B) It emits light only when it is forward biased.

(C) It emits light only when it is reverse biased.

(D) The energy of the light emitted is equal to or slightly less than the energy gap of the semiconductor used.

Photodiode is a device

The material used for solar cell should have band gap

(A) equal to zero.

(B) equal to $0.08$ eV.

(C) between $1.0$ eV to $1.8$ eV.

(D) equal to $2$ eV.

In the following circuit, the current through the Zener diode is

The Zener diode has reverse breakdown voltage $V_Z$. The current through the load resistance $R_L$ is $I_L$. The current through Zener diode is

($V_0$ = Input voltage, $R_S$ = Series resistance)

An ideal Zener diode with breakdown voltage of -3 V is reverse biased with a negative input voltage $V_i = -5\text{ V}$. The magnitude of voltage difference between point $B$ and $A$ is:

The following diagram shows a Zener diode as a voltage regulator. The Zener diode is rated at $V_z = 5\text{ V}$ and the desired current in load is 5 mA. The unregulated voltage source can supply upto 25 V. Considering the Zener diode can withstand four times of the load current, the value of resistor $R_s$ (shown in circuit) should be $\underline{\qquad\quad}\ \Omega$.

A diode has Zener voltage of 10 V and maximum power dissipation of 0.5 W, then the minimum resistance to be used in series with this diode for safety when it is connected to a 25 V power supply is $\underline{\qquad\quad}\ \Omega$.

A voltage regulating circuit consisting of Zener diode, having break-down voltage of 10 V and maximum power dissipation of 0.4 W, is operated at 15 V. The approximate value of protective resistance in this circuit is $\underline{\qquad\quad}\,\Omega$.

The maximum rated power of the LED is 2 mW and it is used in the circuit with input voltage of 5 V as shown in the figure below. The current through resistance $R_S$ is 0.5 mA.

The minimum value of the resistance of $R_S$, to ensure that the LED is not damaged is $\underline{\qquad\quad}\ \text{k}\Omega$.

The graph given below represents I-V characteristics of zener diode. The part of the characteristics curve that is most relevant for its operation as a voltage regulator is

When LED is manufactured by using aluminium gallium arsenide (AlGaAs), it emits

$\text{I} - \text{V}$ characteristics of LED is shown correctly by graph

I - V characteristics of photodiode for different illumination intensities $\text{I}_1, \text{I}_2, \text{I}_3$ and $\text{I}_4$ are drawn as follows. Then the maximum intensity among them is

The material used for solar cell should have band gap

In the following circuit, the reading of the ammeter will be

$($ Take Zener breakdown voltage $= 4\text{ V})$

A zener diode with 5 V zener voltage is used to regulate an unregulated dc voltage input of 25 V. For a $400\,\Omega$ resistor connected in series, the zener current is found to be 4 times load current. The load current $(I_L)$ and load resistance $(R_L)$ are:

Consider the following statements:

A. The junction area of solar cell is made very narrow compared to a photo diode. B. Solar cells are not connected with any external bias.

C. LED is made of lightly doped p-n junction.

D. Increase of forward current results in continuous increase of LED light intensity. E. LEDs have to be connected in forward bias for emission of light.

Choose the correct answer from the options given below:

A light emitting diode (LED) is fabricated using GaAs semiconducting material whose band gap is $1.42\text{ eV}$. The wavelength of light emitted from the LED is:

For detecting light intensity we use

In the working of photodiode, the reverse current depends on

Conductivity of a photodiode starts changing only if the wavelength of incident light is less than $660\text{ nm}$. The band gap of photodiode is found to be $\left(\frac{\text{X}}{8}\right)\text{eV}$. The value of $\text{X}$ is:

(Given, $\text{h} = 6.6 \times 10^{-34}\text{ Js}, \text{e} = 1.6 \times 10^{-19}\text{ C}$)

The I-V characteristics shown above are exhibited by a

The $I\text{-}V$ characteristics of an electronic device are shown in the figure. The device is:

In the given circuit, Zener breakdown voltage is 8 V. If power of Zener diode is 1.6 W. The value of $R$ is

In the circuit diagram shown in figure, the current through the zener diode is

A zener diode, having breakdown voltage 15 V is used in a voltage regulator circuit as shown. The current through the zener diode is

In the given circuit if the power rating of Zener diode is $10\text{ mW}$, the value of series resistance $R_s$ to regulate the input unregulated supply is:

A Zener diode of breakdown voltage $10\text{ V}$ is used as a voltage regulator as shown in the figure. The current through the Zener diode is:

In the given circuit, the breakdown voltage of the Zener diode is $3.0\text{ V}$. What is the value of $\text{I}_\text{z}$?

Consider the following statements A and B and identify the correct answer:

A. For a solar-cell, the I-V characteristics lies in the IV quadrant of the given graph. B. In a reverse biased $pn$ junction diode, the current measured in $(\mu\text{A})$, is due to majority charge carriers.

A potential divider circuit is connected with a dc source of $20\text{ V}$, a light emitting diode of glow in voltage $1.8\text{ V}$ and a zener diode of breakdown voltage of $3.2\text{ V}$. The length (PR) of the resistive wire is $20\text{ cm}$. The minimum length of PQ to just glow the LED is _________ $\text{cm}$.

Choose the correct statement about Zener diode:

For emission of light, a light emitting diode (LED) is

Which one of the following statements is WRONG regarding LED?

Which one of the following statement is not correct in the case of light emitting diodes? A. It is a heavily doped p-n junction.

B. It emits light only when it is forward biased.

C. It emits light only when it is reverse biased.

D. The energy of the light emitted is equal to or slightly less than the energy gap of the semiconductor used.

Choose the correct answer from the options given below:

Identify the mismatch out of the following.

Given below are two statements:

Statement I: Photovoltaic devices can convert optical radiation into electricity.

Statement II: Zener diode is designed to operate under reverse bias in breakdown region. In the light of the above statements, choose the most appropriate answer from the options given below:

A $5.0\text{ V}$ stabilized power supply is required to be designed using a $12\text{ V}$ DC power supply as input source. The maximum power rating of zener diode is $2.0\text{ W}$. The minimum value of resistance $R_\text{s}$ in $\Omega$ connected in series with zener diode will be

A zener diode of power rating 1.6 W is to be used as voltage regulator. If the zener diode has a breakdown of 8V and it has to regulate voltage fluctuating between 3 V and 10 V. The value of resistance Rs for safe operation of diode will be

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R

Assertion A: Photodiodes are used in forward bias usually for measuring the light intensity. Reason R: For a p-n junction diode, at applied voltage V the current in the forward bias is more than the current in the reverse bias for $|\text{V}_\text{z}| > \pm \text{V} \geq |\text{V}_0|$ where $\text{V}_0$ is the threshold voltage and $\text{V}_\text{z}$ is the breakdown voltage.

In the light of the above statements, choose the correct answer from the options given below

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R

Assertion A: Photodiodes are preferably operated in reverse bias condition for light intensity measurement.

Reason R: The current in the forward bias is more than the current in the reverse bias for a $p - n$ junction diode.

In the light of the above statements, choose the correct answer from the options given below:

The following graph represents

Identify the correct circuit diagrams for the normal operation from the following.

The incorrect statement about the property of a Zener diode is:

The energy band gap of semiconducting material to produce violet (wavelength = 4000$\text{\AA}$) LED is ______________ $\text{eV}$. (Round off to the nearest integer).

Identify the solar cell characteristics from the following options:

A $8\text{ V}$ Zener diode along with a series resistance $\text{R}$ is connected across a $20\text{ V}$ supply (as shown in the figure). If the maximum Zener current is $25\text{ mA}$, then the minimum value of R will be _______ $\Omega$.

In the circuit shown below, maximum zener diode current will be _________ $\text{mA}$.

The circuit diagram used to study the characteristic curve of a zener diode is connected to variable power supply (0 $-$ 15 V) as shown in figure. A zener diode with maximum potential Vz = 10 V and maximum power dissipation of 0.4 W is connected across a potential divider arrangement. The value of resistance RP connected in series with the zener diode to protect it from the damage is ________________ $\Omega$.

In the given circuit, the value of current IL will be ____________ mA. (When RL = 1k$\Omega$)

The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because:

The I-V characteristics given in above figure is related to:

A zener of breakdown voltage Vz = 8 V and maximum zener current, IZM = 10 mA is subjected to an input voltage Vi = 10 V with series resistance R = 100 $\Omega$. In the given circuit RL represents the variable load resistance. The ratio of maximum and minimum value of RL is _____________.

Consider the following statements (A) and (B) and identify the correct answer.

(A) A Zener diode is connected in reverse bias, when used as a voltage regulator. (B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.

LED is manufactured using zinc selenide then it emits.

LED is constructed from Ga-As-P semiconducting material. The energy gap of this LED is 1.9 eV. Calculate the wavelength of light emitted and its colour.

[h = 6.63 $\times$ 10$-$34 Js and c = 3 $\times$ 108 ms${}^{-1}$]

Consider a situation in which reverse biased current of a particular P-N junction increases when it is exposed to a light of wavelength $\leq$ 621 nm. During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly.

Zener breakdown occurs in a p $-$ n junction having p and n both:

For the circuit shown below, calculate the value of Iz:

A zener diode of power rating 2W is to be used as a voltage regulator. If the zener diode has a breakdown of 10 V and it has to regulate voltage fluctuated between 6 V and 14 V, the value of Rs for safe operation should be ___________ $\Omega$.

For the given circuit, the power across Zener diode is .............. mW.

In a given circuit diagram, a 5 V zener diode along with a series resistance is connected across a 50 V power supply. The minimum value of the resistance required, if the maximum zener current is 90 mA will be __________ $\Omega$.

A zener diode having zener voltage 8 V and power dissipation rating of 0.5 W is connected across a potential divider arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance Rp is .................... $\Omega$.

The value of power dissipated across the zener diode (Vz = 15V) connected in the circuit as shown in the figure is x $\times$ 10$-$1 watt.

The value of x, to the nearest integer, is __________.

The zener diode has a Vz = 30V. The current passing through the diode for the following circuit is ________ mA.

A p-n junction photodiode is fabricated from a semiconductor with a band gap of $2.5\text{ eV}$. It can detect a signal of wavelength [Planck's constant $= 6.6 \times 10^{-34}\text{ Js}, \text{c} = 3 \times 10^{8}\text{ m/s}, \text{e} = 1.6 \times 10^{-19}\text{ C}$]

If a semiconductor photodiode can detect a photon with a maximum wavelength of 400 nm, then its band gap energy is:

Planck’s constant h = 6.63 $\times$ 10–34 J.s. Speed of light c = 3 $\times$ 108 m/s

With increasing biasing voltage of a photodiode, the photocurrent magnitude:

Two Zener diodes (A and B) having breakdown voltages of 6 V and 4 V respectively, are connected as shown in the circuit below. The output voltage V0 variation with input voltage linearly increasing with time, is given by:

(Vinput = 0 V at t = 0)

(figures are qualitative)

Take the breakdown voltage of the

zener diode used in the given circuit as 6V.

For the input voltage shown in figure below,

the time variation of the output voltage is:

(Graphs drawn are schematic and not to scale)

The circuit shown below is working as a 8 V dc regulated voltage source. When 12 V is used as input, the power dissipated (in mW) in each diode is; (considering both zener diodes are identical) _________.

$V - I$ characterstics of LED is shown correctly by graph

An LED is constructed from a p-n junction diode using GaAsP. The energy gap is $1.9\text{ eV}$. The wavelength of the light emitted will be equal to

Figure shows a DC voltage regulator circuit, with a Zener diode of breakdown voltage = 6V. If the unregulated input voltage varies between 10 V to 16 V, then what is maximum Zener current?

The figure represents a voltage regulator circuit using a Zener diode. The breakdown voltage of the Zener diode is 6 V and the load resistance is, RL = 4k$\Omega$. The series resistance of the circuit is Ri = 1 k$\Omega$. If the battery voltage VB varies from 8 V to 16 V, what are the minimum and maximum values of the current through Zener diode?

The reverse breakdown voltage of a Zener diode is 5.6 V in the given circuit.

The current IZ through the Zener is:

In the given circuit the current through Zener Diode is close to:

For the circuit shown below, the current through the Zener diode is -

In the given circuit, the current through zener diode is:

An experiment is performed to determine the I - V characteristics of a Zener diode, which has a protective resistance of R = 100 $\Omega$, and a maximum power of dissipation rating of 1 W. The minimum voltage range of the DC source in the circuit is:

Identify the semiconductor devices whose characteristics are given below, in the order $(a), (b), (c), (d)$:

The value of the resistor, RS, needed in the dc voltage regulator circuit shown here, equals:

For LED's to emit light in visible region of electromagnetic light, it should have energy band gap in the range of:

A Zener diode is connected to a battery and a load as shown below:

The currents I, IZ and IL are respectively

The given graph represents V-I characteristic for a semiconductor device.

Which of the following statement is correct?

The $\text{I-}V$ characteristic of an $LED$ is

A Zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit shown in figure. The current through the diode is

A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength

A p-n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly

Zener diode is used for

In a p-n junction photo cell, the value of the photo-electromotive force produced by monochromatic light is proportional to