when a diode is operated inthe reverse biased condition, the width of the depletion region increases as voltage that is applied increases. Varying the width of the depletion region is equivalent to varying the plate separation of a very small capacitor such that the relationship between junction capacitance & applied reverse voltage will look something like that presented in figure below. The typical variation of capacitance supplied by a varactor is from about 50pF to 10pF as the reverse voltage goes up from 2V to 20V. The symbol used for a varactor diode has been shown above.Varactor diodes
when a diode is operated inthe reverse biased condition, the width of the depletion region increases as voltage that is applied increases. Varying the width of the depletion region is equivalent to varying the plate separation of a very small capacitor such that the relationship between junction capacitance & applied reverse voltage will look something like that presented in figure below. The typical variation of capacitance supplied by a varactor is from about 50pF to 10pF as the reverse voltage goes up from 2V to 20V. The symbol used for a varactor diode has been shown above.Transistor operating configurations
There are 3 basic circuit configurations that are used for transistor amplifiers. These 3 circuit configurations depend upon which one connection among the 3 transistor connections is made common to both the input and the output. In the case of bipolar junction transistors, the configurations are referred to as common emitter, common collector or emitter follower, & common base, as shown in diagram below.
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Analogue instruments
All analogue electrical indicating instruments need 3 essential devices these devices are briefly discussed below:
1- A deflecting or operating device.
A mechanical force is generated by the current or voltage which causes the pointer to have some deflecition from its 0 position.
2- A controlling device.
The controlling force works in opposition to the deflecting force & ensures that the deflection being shown on the meter is always the same for a given measured quantity. It also pr events the pointer always going to maximum level of deflection. There are 2 main types of controlling devices, which includes spring control & gravity control.
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1- A deflecting or operating device.
A mechanical force is generated by the current or voltage which causes the pointer to have some deflecition from its 0 position.
2- A controlling device.
The controlling force works in opposition to the deflecting force & ensures that the deflection being shown on the meter is always the same for a given measured quantity. It also pr events the pointer always going to maximum level of deflection. There are 2 main types of controlling devices, which includes spring control & gravity control.
The superposition theorem
This tutorial is superposition theorem. The superposition theorem states:
‘In any network which is made up of linear resistances & containing more than 1 source of e.m.f., the resultantcurrent flowing in any branch is the algebraic sum of the currents that would flow in that branch if eachsource was considered separately, all other sourcesbeing replaced at that time by their respective internal resistances.’
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‘In any network which is made up of linear resistances & containing more than 1 source of e.m.f., the resultantcurrent flowing in any branch is the algebraic sum of the currents that would flow in that branch if eachsource was considered separately, all other sourcesbeing replaced at that time by their respective internal resistances.’
Delta and star connections
The network presented below in Figure 34.1-a) containing 3 impedances Z A, ZB and ZC is said to be π-connected.such network can be redrawn as drawn in Figure 34.1(b),where the arrangement is said to be as delta-connectedor mesh-connected.
The network drawn in Fig 34.2-a, containing of 3 impedances, Z1, Z2 and Z3, is referred to beT-connected. This network can be redrawn as drawn in Figure 34.2(b), where the arrangement is referred to as star-connected.
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The network drawn in Fig 34.2-a, containing of 3 impedances, Z1, Z2 and Z3, is referred to beT-connected. This network can be redrawn as drawn in Figure 34.2(b), where the arrangement is referred to as star-connected.
Current and voltage relationships
Figure 44.3 below presents us a voltage source VS supplied to the input terminals of an infinite line, or a line terminated in its characteristic impedance, so that a current IS flows into the line.At a point, say, one km down the line let the current be I1. The current I1 will not have the same magnitude as IS because of line attenuation; also I1 willlag IS by some angle β. The ratio IS/I1 is therefore aphasor quantity. Let the current a further onekm down theline be I2, & so on, as demonstrated in Figure 44.3 below. Each unit-length of line can be considered as a section of a repetitive network. The attenuationis in the form of a logarithmic decay &
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Advanced Electronics formulas
Below is the List of Advanced Electronics formulas:
- Comlex numbers formulas
- LR-C network formula
- LR-CR formulas
- Advanced Electronics Determinants
- Delta star formula
- Star delta formula
- Impedance matching formula
- Formulas for R-L-C series circuits
- Fourier series formulas
- Field theory Formulas
- Harmonic Analysis Formulas
- Formulas for Hysteresis and Eddy current
Shunts and multipliers
An ammeter, which is used for measuring current, offers a low level resistance (ideally 0) & must be connected in series with the circuit.
A voltmeter, which is used for measuring p.d., offers a high level of resistance (ideally I has infinite) & must be connected in parallel with the part of the circuit whose p.d. is required. There is no difference between the basic instrument used to measure current and voltage because both make of use a milliamp meter as their basic part. This is a sensitive instrument which gives f.s.d. for currents of just a few milli amperes. When an ammeter is needed to measure currents of having large magnitudes, a proportion of the current is diverted through a low-value resistance connected in parallel with the meter. Such a diverting type of resistor is referred to as shunt.
Moving-iron instrument
There are two types of moving iron instrument which are discussed below briefly
Attraction type
Figure (a) below demonstrates an attraction type of moving-iron instrument is When current flows in the solenoid, a pivoted soft-iron disc is attracted towards the solenoid & themovement causes a pointer to have some movement across a scale.
Electrical Engineering Formulas (principles and technology)
A.C Theory: all Formulas for a.c circuits
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Passive networks and reciprocity theorem
The ABCD parameters for a 2-port network are:
V1 = AV2 −BI2 (28)
I1 = CV2 −DI2 (29)
Figure shown below shows a two-port network whose terminals RS are short-circuited with an input voltage V across terminals PQ. Then V2 in the above equations is 0 and the equations become:
V =−BI2 (31)
and I1 =−DI2 (32)
