The dominant mechanism for motion of charge carriers in forward and reverse biased silicon P-N junction are :
Theory: In forward biased mode diffusion current is more than drift current. Where as in reverse biased mode diffusion current decreased and become less than drift current.
In the given circuit
The current through the battery is :
Diode D2 and D3 are forward biased. Where as Diode D1 is reversed biased. No current will flow through D1.
Equivalent Resistance= 20/3 ohm
Current = Voltage / Resistance = 10/ (20/3) = 1.5 Ampere
Phodiode, zenerdiode and solar cell is used in:
A Photodiode and Zener Diode operate in Reverse Bias, while a Solar Cell operates in an Unbiased condition (zero external voltage).
Which of the following statement is not correct when a junction diode is in forward bias :
In forward bias, the applied field opposes the barrier field, pushing major carriers (electrons on n-side and holes on p-side) towards the junction, thereby decreasing the depletion width. Thus, statement (4) is incorrect.
The approximate ratio of resistances in the forward and reverse bias of the PN-junction diode is :
Forward resistance of a diode is very small (\(approx 10\Omega\)), while its reverse resistance is extremely high (\(approx 10^5 \Omega\)). The ratio \(R_f / R_r\) is of the order of \(10^{-4}\), which corresponds to \(1 : 10^4\).
A p-type extrinsic semiconductor is obtained when Germanium is doped with
A p-type semiconductor is created by doping a tetravalent semiconductor (like Ge) with a trivalent impurity such as Boron.
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.
A Zener diode regulates voltage when reverse-biased in the breakdown region (A is correct). The potential barrier for a Silicon p-n junction is around 0.7 V, which is outside the 0.1 V to 0.3 V range (B is incorrect).
The electron concentration in an \(n\)-type semiconductor is the same as hole concentration in a \(p\)-type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them.
The mobility of electrons (\(mu_e\)) is greater than the mobility of holes (\(mu_h\)). Since current is proportional to mobility for the same carrier concentration and electric field, the current in the \(n\)-type semiconductor is greater than that in the \(p\)-type.
A silicon (Si) specimen is doped with aluminium (Al). The concentration of acceptor atoms is \(10^{18}\text{ m}^{-3}\). Given that the intrinsic carrier concentration is \(10^{16}\text{ m}^{-3}\), the concentration of electrons in the specimen is
Formula: \(n_e n_h = n_i^2\). Since the semiconductor is heavily p-doped, \(n_h approx N_a = 10^{18}\text{ m}^{-3}\). Therefore, \(n_e = frac{n_i^2}{n_h} = frac{(10^{16})^2}{10^{18}} = 10^{14}\text{ m}^{-3}\).
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): A digital circuit that follows logical relationship between the input and output voltages are generally known as logic gates.
Reason (R): NOR and NAND gates are not considered as universal gates.
In the light of above statements, choose the correct answer from the options given below.
Assertion is true because logic gates process signals based on logical relationships. Reason is false because NAND and NOR gates can implement any Boolean function, meaning they are universal gates.