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Calculate the potential barrier for a Germenium PN junction at room temperature, if both the P – and N- regions are doped equally and to the extent of one atom per 106 Ge atoms. (Given ni = 2.4×1019/m3 and NA=ND=(4.4×1028)/106 =4.4×1022/m3.
When a reverse bias is applied to a germanium PN junction diode, the reverse saturation current at room temperature is 0.3 µA. Determine the current flowing in the diode when 0.2 V forward biases is applied at room temperature.
The reverse saturation current of a silicon PN junction diode is 20µA. Calculate the diode current for the forward bias voltage of 0.7 V at 25 C.
The diode current is 0.5 mA when the applied voltage is 400 mV and 20 mA when the applied voltage is 500 mV. Determine ȵ. Assume kT/ q = 25mV.
Calculate the junction capacitance of a Ge diode whose area is 1 mm× 1mm and depletion region width is 2µm. The relative permittivity of Ge is 16.
The junction capacitance of an abrupt junction diode is 20 pF at 5 V. Compute the decrease in capacitance for 1 V increase in bias.
light-emitting diode is made of GaAsP having a band gap of 1.9eV. Determine the wavelength and colour of radiation emitted.
Calculate the wavelength of emission from GaAS diode, if the band gap in GaAs is 1.44eV
The InGaAs diode laser has peak emission wavelength of 1.55µm. Determine its band gap.
What optical power at a wavelength of 1.55µm would give a photo current that is twice the dark current 5X10-9 A and responsivity 0.87A/W? What is Quantum efficiency of the photo detector at 1.55 µm.
Calculate the responsivity of a photo sensitive material with a quantum efficiency of 1% at 500 nm.
A Photodiode has a responsivity of 0.5A/W at 850nm. Find the efficiency of the detector.
Unit-III
Unit-III
A half wave rectifier, having a resistive load of 1000 Ω rectifies an alternating voltage of 325 V peak value and the diode has a forward resistance of 100 Ω. Calculate (a) peak, average and rms value of current (b) dc power output (c) ac input power, and (d) efficiency of the rectifier.
A half wave rectifier is used to supply 24 V dc to a resistive load of 500 Ω and the diode has a forward resistance of 50 Ω. Calculate the maximum value of the ac voltage required at the input.
An ac supply of 230 V is applied to a half wave rectifier circuit through transformer of turn ratio 5:1. Assume the diode is an ideal one. The load resistance is 300 Ω. Find (a) dc output voltage (b) PIV (c) maximum, and (d) average values of power delivered to the load.
A full wave rectifier circuit uses two silicon diodes with a forward resistance of 20 Ω each. A dc voltmeter connected across the load of 1 kΩ reads 55.4 Volts. Calculate (a) Irms, (b) Idc and (c) ripple factor.
A full wave rectifier delivers 50 W to a load of 200 Ω. If the ripple factor is 1%, calculate the ac ripple voltage across the load.
Calculate the value of inductance to use in the inductor filter connected to a full wave rectifier operating at 60 Hz to provide a dc output with 4% ripple for a 100 Ω load.
Calculate the value of capacitance to use in capacitor filter connected to a full wave rectifier operating at a standard aircraft power frequency of 400 Hz, if the ripple factor is 10% for a load of 500 Ω.
Design a filter circuit for full wave circuit with LC filter to provide an output voltage of 10 V with a load of 200 mA and the ripple is limited to 2%.
Unit-IV
Unit-IV
In a common base transistor circuit, the emitter current is 10 mA and collectror current is 9.8 mA. Find the value of base current.
The common base DC current gain of transistor is 0.967. If the Emitter current is 10 mA. What is the value of base current?
If a transistor has a α value of 0.97. Find the value of β. If β= 200 find the value of α.
A transistor has β= 150.Find Ic and IB if IE= 10 mA.
For a transistor circuit having α=0.98 and ICBO=5 µA, IB=100 µA. Find the values of Find Ic and IE.
Determine Ic and IE and α for a transistor circuit having IB= 15 µA and β= 150.
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