An increase in junction temperature of a semiconductor diode
Reverse saturation current doubles for every 10ºC rise in junction temperature.
An air gap provided in the iron core of an inductor prevents
Generally, the gain of a transistor amplifier falls at high frequency due to the
Which of these has a layer of intrinsic semiconductor?
The intrinsic layer is in between p and n layers.
Assertion (A): When Diode used as rectifier the reverse breakdown voltage should not be exceeded.
Reason (R): A high inverse voltage can destroy a p-n junction.
PIV is an important parameter in rectifier operation.
A Si sample is doped with a fixed number of group N impurities. The electron density n is measured from 4 K to 1200 k for the sample. Which one of the following is correct?
Assertion (A): In design of circuit using BJT, a derating factor is used.
Reason (R): As the ambient temperature increases, heat dissipation becomes slower.
Increase of ambient temperature lowers the heat dissipation capacity.
Therefore derated operation of BJT is necessary lest BJT should be destroyed.
If the drift velocity of holes under a field gradient of 100 V/m is 5m/sec. Their mobility is
E = μ . Vd μ =.
In a P type silicon sample, the hole concentration is 2.25 x 1015 / cm3. If the intrinsic carrier concentration is 1.5 x 1010/ cm3 the electron concentration is
Electron concentration .
The behaviour of a JFET is similar to that of
Both JFET and vacuum triode are voltage controlled devices.
What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode?
Since the duration of output waveform is less than 180º, output voltage is less than input voltage.
As temperature increases the number of free electrons and holes in an intrinsic semiconductor
Increase of temperature increases conductivity of semiconductors.
At room temperature kT = 0.03 eV.
Assertion (A): A JFET behaves as a resistor when VGS < VP.
Reason (R): When VGS < VP, the drain current in a JFET is almost constant.
In a reverse biased P-N junction, the current through the junction increases abruptly at
Dielectric strength of polythene is around
Resistivity of hard drawn copper is
The channel of JFET consists of
The channel in JFET may be n type or p type. If channel is n type, gate is p type and if channel is p type gate is n type.
In a bipolar junction transistor adc = 0.98, ICO= 2 μA and 1B = 15 μA. The collector current IC is
The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage that will occur on the reverse biased diode will be
Assertion (A): The forward resistance of a p-n diode is not constant.
Reason (R): The v-i characteristics of p-n diode is non-linear.
If v-i characteristics is non linear, the ratio v-i is not constant.
For a photoengraving the mask used is
The mask that is prepared first is called the master mask made from glass substrates covered by thin chromium film.
From the master masks are prepared working masks by contact pointing and used for Photolithography which means Photo engraving.
In a varactor diode the increase in width of depletion layer results in
Capacitance is inversely proportional to distance between plates.
In given figure a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20ºC, VD is found to be 700 mV. If the temperature rises to 40ºC, VD becomes approximately equal to
Id = Io(eVD/ηVT - 1)
By considering , then
Id is constant according to question,
VD a T
The work function of a photo surface whose threshold wave length is 1200 A, will be