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  Determine the resistor value required to use 0-1 mA meter with an internal resistance of 125 Ω for a 0-1 V meter. Ans. _ e = 1v, I = 1mA, r = 125 Ω R = e/𝐼 − 𝑟 = 1𝑣 /1𝑚𝐴 − 125 Ω  = 1000 − 125Ω = 875 Ω  Hence, the required Resistor value is 875 Ω.

Ammeter and Voltmeter are connected in series and parallel respectively. Why? Ans. In series connection, the same current flows through all the components.  Ammeter aims at measuring the current flowing through the circuit and hence, it is  connected in series, so that the same current that is there in the circuit flows through  it and gets measured. Voltmeter aims at measuring the amount of potential difference across a resistor or  series of resistor. A voltmeter measures the potential difference of the circuit and it  has high internal resistance. When the voltmeter is connected in parallel with a circuit  component, the amount of current passing through the voltmeter is very less.  Therefore, the current through the circuit is unaltered.

Discribe the working of PMMC meter. Ans . The PMMC stands for permanent magnet moving coil and it is also called as D’Arsonval instruments. The PMMC works on the electromagnetic effect. A permanent magnet is used to produce magnetic flux and a coil that carries the current to be measured moves in this field. As the pointer is connected to the coil it gets deflected in proportion with the current. When a current carrying conductor placed in the magnetic field experiences a force. It is given by the expression is given below, F=BIL Where, F=Force in Newton, B= Flux density in Tesla, I= Current in ampere, L= Length of conductor in meter

Explain the analysis of RLC network with and without initial condition with the help of laplace. 

Proof maximum power transfer theorem.  Let us consider a two Terminal network.  The original two terminal circuit is replaced with a Thevenin’s equivalent circuit across the variable load resistance. The current through the load for any value of load resistance is On  differentiating PL with respect to RL and equate to 0, we get Now substituting RL with Rth in PL then the maximum power delivered to the load is

Explain the duality of network with example.  A dual of a relationship  is one  in which current and voltage are interchangeable two networks are dual to each other if one has mesh equation numerically identical to others node equation .  According to duality of network there are some dual pairs: Elements            Dual elements voltage                current  short circuit        open circuit  series                  parallel  Norton                 Thevenin  resistance           conductance  impedance         admittance  KVL                     KCL  capacitance        inductance

What is the difference between planar and non- planar graph?  PLANNER GRAPH :- • A graph in which the direction of current or direction or of Edge is given is called planar graph.  • planar graph is also known as oriented graph.  Non-Planar graph:- •  A graph in which the direction of current age is not given is called Non - Planar graph.  • Non- planar graph is also known as unoriented graph. 

Explain the following terms:- Tree :- it is a inter-connected open set of branches which include all the nodes at a given graph without forming any closed path.  Co- Tree :- From the oriented graph, if a tree is removed, the resultant is known as co tree or complement of tree.  Link :- It is a branch of a graph which does not belong to the particular tree, known as link . The link are present in the tree.  Graph :- The graph is also called as the collection of different points called as the node and different lines called as elements. These buses are interconnected through elements.  Nodes :- A point where two or more circuit elements branches meet is called a node.  Loop : - loop is a closed path of a circuit but all match are loops and the loop is not necessarily a mesh. 

Calculate the pic rating of the diode used in the full wave rectifier shown as . Also find the maximum DC voltage that can be obtained from the circuit. mark the polarity on the millimetre.  Solution :- Number of turns in primary binding Np = 1000 Number of turns in secondary binding Ns = 50 Vp = 220 V Np/Ns = Vp/Vs 1000/50= 220/Vs Vs = 11v Vrms = Vm/√2  => Vm = Vrms √2 => Vm = 11 √2 Vm = 15.5563 v Vdc = 2Vm /π Vdc = 15.5563/π = 9.90V I = V/R => 9.90/1×1000 I = 9.9mA PIV  = 2Vm = 2 × 15.5563   PIV= 31.112 V

Calculate the maximum DC voltage available from a half wave rectifier Shown . Also find the reading of the milli ammeter.  Solution:- Turn ratio of transformer = 20:1 Number of turns in primary binding = 20 Number of turns in secondary binding = 1 Mains voltage supply(1/p) Vp = 220 v From the Transformer ratio formula Np/Ns = Vp/Vs 20/1 = 220/ Vs Vs = 220/20 = 11V Vrms = Vm/√2  => Vm = Vrms √2 => Vm = 11 √2 Vm = 15.5563 v Vdc =  2Vm /π Vdc = 2×15.5563/π = 9.90V I = V/R => 9.90/1×1000 I = 9.90mA

What do you mean by zener diode, explain its working principle with neat and clean diagram?  Zener diode is a special type of diode designed to reliably allow current to flow "backward" (that is Reverse Biased) when a certain set reverse voltage known as a zener voltage is reached. zener diode are manufactured with a great variety of Zener voltage and some even variable.  Working principle:- When a PN junction diode is highly doped ,  then concentration of impurity atoms will be high in the Crystal. The higher concentration of impurity atoms cause the highest concentration of ions in the depletion layer. Hence for some applied reverse Bias Voltage the width of depletion layer , becomes than that  in a normally doped diode due to thinner depletion layer, voltage gradient for electric field strength across the depletion layer is quite high. if the reverse voltage is continued to increase, after a certain applied voltage , the electron from the covalent bonds  with...

What do you mean by bleeder resistor?  Bleeder Resistor is a resistor connected in a parallel with the output of a High Voltage power supply circuit for the purpose of discharging the electric charge stored in the power supply is filter capacitor when the equipment is turned off , for safety reasons. 

Explain the following: (I) PN junction diode in forward bias:- When a diode is connected in a forward bias condition a negative voltage is applied to the n type material and a positive voltage is applied to the P type material. If the external voltage becomes greater than the value of potential barrier which is 0.7 volt for Silicon and 0.3 for Germanium then current will start to flow.  (II) Zener effect:- Zener Effect /diode is a type of electrical breakdown. it occurs in the reverse bias PN junction diode when the electric field enables tunneling of the electron from the valence to the conduction band of a semiconductor, leading to numerous free minority carrier which suddenly increased the reverse current.  (iii)   Avalanche effect : - It is a sudden rapid increase in the current when a sufficient amount of electrical force is applied to the semiconductor material.  (iv) Reverse saturation current :- It is a kind of leakage current or invented current flows w...

Write a short note on formation of depletion region.  A PN junction is formed using a positive and negative semiconductor.  When the two semiconductor are joined together , the electron from the n-side are diffused to the n- reason and they form a layer of negative charges from the pyside are diffuse to the end the season and they form a layer of positive charge on the n - side . The reason between those two layer is the depletion region of the semiconductor. 

Write the characteristic of ideal diode.  The characteristic of ideal diode are:- Threshold voltage:- ideal diode do not have a threshold voltage once any forward voltage is applied across the diode it will conduct current instantly across it's Junction.  Forward current:-   when ideal diode is forward biased it allowed full current to pass through it that is it act as a conductor due to internal resistance of diode would be zero .  Breakdown voltage:-  ideal diode to not have a breakdown voltage. This because when diode is Reverse bias no any current pass through it that is act as an insulator and shows full resistance.  Reverse leakage current:- As an ideal diode not contain breakdown end , it never perform any reverse current or reverse leakage current. 

Derive the Ripple factor and efficiency in case of half wave and full wave rectifier circuit .  Ripple factor: - Ripple factor is the ratio of RMS value of AC component present in the rectified output to the average value of rectified output. it is  dimensionless quantity.  Rectification efficiency:- it is a quantitative measurement of rectifier efficiency . it is ratio of DC power output to AC power input to the rectifier. it is denoted and expressed in percentage.  Derivation of Ripple factor: By definition, The RMS value of total load current is given by I rms = √( I dc)^2+ ( I ac) ^2 (or) Iac = √ I rms ^2+ I dc^2 When the above equation is divided by using Idc then we can get the following equation. Iac / Idc = 1/ Idc √I2rms + I2dc However, here Iac / Idc is the ripple factor formula R.F = 1/ Idc √I2rms + I2dc = √ (Irms / Idc)2 -1 Ripple Factor of Half Wave Rectifier For half-wave rectifier, Irms = Im/2 Idc = Im/ π We know the formula of R.F = √ (Irms / Idc...

Why bridge rectifier mostly used for AC to DC conversion?  Bridge rectifier are mostly used AC to DC conversion because peak inverse voltage rating of diode in bridge rectifier is half than that of needed in Centre tapped full wave rectifier . Diode used in bridge rectifier are capable of Bearing Heig pick inverse voltage. 

What do you mean by additive property of diode?  In full wave Centre tapped rectifier , two diodes are used D1 and D2 during the positive half cycle of secondary voltage . That diode D1 is forward bias and D2 is Reverse Biased, then the current flow in the direction of load . During negative half cycle due to becomes forward bias and then becomes reverse Biased then the direction of current is same as direction of current in positive cycle flowing in load . Hence, the direction of load current in both cases are same. This property of centre tapped rectifier is known as as  additive property of diode. 

Differentiate between half wave and full wave with respective filter theory?  According to filter theory, the filter convert pulsating direct current into pure current. The working of the full wave  rectifier and half wave rectifier is almost similar with the filter. Since both rectifier use filter to decrease the ripple DC. But the only difference is that in the half rectifier only one half cycle other positive or negative of the input AC current will change the capacitor , but the remaining half cycle will not charge the capacitor.  In the full wave rectifier both positive and negative half cycles of input AC current will charge the capacitor

How the concentration /doping affects the nature of the diode in diode operation?  When the amount of doping increases the thickness of depletion layer generated at the junction decreases and when the amount of doping decreases layer increases . Even if one part of PN junction is heavily doped the thickness of depletion layer on that becomes less than that of other side . If the depletion region increases then only some amount of current (as a small leakage) will be slow and diode act like an operation circuit . If the depletion region decreases when diode acts like a short circuit and it allowing full circuit current to flow.