Diploma C25 ECE Applied Electronics-I code 25EC21I Model Question Paper-2 part -D 10marks 💯 2nd sem

Added: 2026-05-22

[00:00:00]Dear students, welcome to my channel.

[00:00:02]This is a model question paper two electronics and communication semester 2 applied electronics one. Subject code is 25 EC 21 high. Uh part D questions. So each question carries 10 marks. If you attend the you will get a 30 marks. So each question will be an 10 marks.

[00:00:23]Describe the atomic structure of silica germanium. illustrate how their atomic structure influence their electrical conductivity and use of using a electrical device. So coming to an in the introduction this are silicon and germanium are semiconductor material it having a trivalent elements having a four valency electrons it's having a both each is having a four valency that we'll show you in the diagram in the periodic table it is a group this group belongs coming to an atomic structure of a silica it is silica atom it is a 14 numbers atomic number is 14 number of electrons are 14 but electronic configuration 2a 8A 4 and silica which is M4 electrons in a outermost. This is the silicon structural diagram. This is the silicon number and electronic configuration valence electrons. This is silicon.

[00:01:16]There's surrounding. You just see the number of valency electron 2 2a 4a 8 which will be around in the silica. This is a diagram you can represent.

[00:01:29]This is an coalent bonding of silicon.

[00:01:31]There's a a coalent bond they given the dotted vertical cube sharing the electron how it will be the sharing the electrons in this diagram you can write this diagram also. Next will be an atomic structure of germanium atoms germanmanium atoms which atomic number is 32 number of electrons revolving around 32. Okay. The configuration coming to the configuration it is having 2 8 18 4 and it is having a four valency electrons.

[00:02:00]Coming to this structure of germanmanium you just see the atomic number and electronic configuration and valency electrons. So you just see how the electrons which will be revolving around here here inside and number of electrons which will be revolving around you can write this diagram and based on the number of electrons you can write it the outermost there's a four electrons and inner eight 18 and two electrons uh it will going to distribute. Okay, coming to a coalent bond. Coming to the coalent bond how it looks in the germanium. You just see the coalent bond. It is a bond and each electron that is this red color which represent electron sharing for all how they're going to represent here the influence of electrical conductivity. Silica germanmanium atom it is a valency electron from coalent bond with an ibering atom. How? in the diagram representing and at the ter room temperature the some coalent bonds break due to heavy heat energy. Okay, this produce free electrons and holes.

[00:03:03]When the free electrons and holes are char this act like a charge carriers and silicon germanium it's having a good conducting electricity moderately that we call it as that's why we call it as an semiconductor. Why we call it as a semiconductor? It is conduct the electricity moderately that we call it as an uh semiconductor. Coming to an uses of silica in electronic devices which we can use it for diode transistor, IC uh IC solas and microprocessor. Same way German same way germanium used for low voltage devices, IP transistors and special detector. You just write a important point about the question. So both silica germanmanium are semiconductor and which it is having a both which having a four valency electrons it conductivity increases when incre with the temperature silica more commonly silicon more commonly used for use because better stability the atomic structure controlled by the electrical behavior of the electrical devices. The next question describe the important so DC load line operating point is BJT BJT amplifier illustrate with the diagram. So coming how it looks uh DC load operating system of QP point in a BJ amplifier. So this is the amplifier surface R1, RB and RC IC will be there.

[00:04:22]So you just see the diagram. Okay, this is diagram for amplification of BJT amplifier. So VB VB VBE and BC voltage collector emitter and base. Okay. So RB and RC this is the diagram will represent you just see the diagram. Okay. And equation based on that equation equation as given VCC is equal to V VC is equal to VCC minus IC and RC when IC becomes zero. So VC VC VC is equal to VC is a cutff point. So IC becomes zero. When VC is zero, how the saturation condition? You can write this formula equation that is also enough for the exam line. What will happen? Right line drawn output characteristics of transistor which will show a possible values of collector current of IC and emitter current of voltage. How the Q point is operating? Uh when the qoint DC line intersecting the transistor, the characteristics we call it as an operating point or Q point. when the DC line when the where the point the DC line which will be intersect which will be intersect with the transistor that we call it as an q point it will be represent zero with the signal condition of the transistor. So coming to an importance of QP point it will be ensure it will give ensure faithful ampl amplification signals which we can use and we can prevent the deteration of output waveforms keep the transistor you can keep the transistor in active region which will be provide a maximum signal swings and it's it will give the stable Q point improve the amplification performance. So okay what is the next we'll go import Important of what is an important of DC load line. Importance of DC load line it helps determine operating region of transistor used for uh to find the q points which show the relation between IC and VCE. It will be L for amplification signal and analysis indicate cutff and saturation region.

[00:06:26]And this qoint should be near to the central load line and improper qoint will cause a deteration. Okay. A load line connected to saturation and cutff points only. The active region will be used for amplification.

[00:06:45]Next will be an DC load line essential for transistor bias.

[00:06:50]Next explain the construction and working principle and characteristics of enhancement type of MSFE and with a symbol and application. This is a you coming uh coming to the diagram which is going to repress a construction diagram NP channel there you just see the diagram how it look it is having a it is having a gate source it is having a gate source silicon insulator SIO2 insulator drain and PN type of uh subtract body this is the body they are going to rep this is the diagram this is an diagram Okay, you just see the diagram and symbol. What is the symbol of enhancement? This is a symbol of enhancement type. Okay, just see the symbol of coming to intro in the introduction. It is a type it we can use for voltage control semiconductor device. So only we can operate how you going to operate with help of when gate voltage is applied we can operates which we can usually widely use for switching and amplification circuit. So coming to an construction the construction of enhancement of MSFE it is having a terminals gate drain and source. So okay NP channel we can used we can it is having a light dropped P type of subtraint we can used okay when two heavy loads dropping okay in NP region which form a source and drain and it get insulated from subtract by thinning silicon dioxide layer there is no physical channel exist between source and drain insul how it will be working principle coming to an working principle This is an working principle. So this is the condition cutff region. CutF region means ID becomes zero. It is an device off when small small R zero gate voltage. There is no inversion the layer formed. There is no existing will be takes place. The diagram look like this.

[00:08:56]You just see the diagram how it looks and symbol also look like this.

[00:09:05]Coming to an explanation working explanation when a gate source wtage vs is zero no channel formed there's no dry current will be zero if it is positive gate is applied the electron attract towards the gate region inversion the layer is formed when a current start flowing the drain so the gate voltage is increases channel conductivity and drain current. So coming to the next condition. So this is the next condition is given channel formed and conduction.

[00:09:35]Okay. So here you just see the condition how it looks. Okay. The positive voltage greater than the attractive electrons to positive surface formed type of inversion channel. Here the device is an on on when the electron from source to drain. When the device is on we are applied WDS. So this is the diagram looks like. This is the symbol for that.

[00:09:57]Next enhance characteristics of enhancement MSFE uh transfer characteristics show the relation between the ID and V VGS the dry current increases rapidly after threshold voltage. So what is the dry characteristic? Dry drying characteristics it show the relationship between ID and VDS. So device will be operate in a cut off region and homic region. Okay.

[00:10:25]and also saturation region. Coming to an application electronic switching circuits we can use power amplification CO integrated circuits, motor control circuits and digital electronics uh we can use. If the content is useful please subscribe my channel, share and support.

[00:10:43]Remaining questions I'm going to upload next video. Thank you.