A Resistor is a passive electronic component having two terminals, that limits the flow of electrons through a circuit. Passive components are the components that can only consume power (they cannot generate power).
Uses of Resistors
The main use of resistors is to reduce the flow of current in a circuit, but it is not limited to this only. Resistors find applications in various fields like- *Resistors can be used to divide voltages (as voltage divider) *To adjust signal levels *Terminating transmission lines *To bias active elements *Timing and frequency applications *In heating applications etc.
Types of Resistors
Resistors can broadly be categorized into two types- *Fixed Resistors *Variable Resistors
Fixed resistors
As clear by its name, fixed resistors cannot change it's value. The fixed resistors can again be classified into following three types- *Carbon composition resistors *Metalized resistors *Wire wound resistors
Variable resistors
The resistance of variable resistors can be changed continually or can be set to a certain value as per the requirement. On the basis of this the variable resistors can again be of two types- *The variable resistors that can change its value continually like that used in volume control applications and *The variable resistors that can be set to a fixed value as desired like in case of potentiometers (adjustable resistor).
Working Principle of resistor
Ohm's Law
For an ideal resistor the Ohm's law is given as - According to Ohm's law the voltage (V) across a resistor is directly proportional to the current (I) flowing through it. Here the constant of proportionality is the resistance (R). This relationship between voltage and current is given as- V=IR
Unit of Resistance (R) and Conductance (G)
Unit of electrical resistance is Ohm (Ω) . Ohm is the SI unit of resistance. Other unit of resistance can be obtained from the Ohm's law. By Ohm's law- R=V/I Therefore the unit of resistance is- Volt per Ampere or V/A. Conductance (G) is opposite to the resistance. Conductance can be defined as the ease with which the current flows through a substance. Formerly the unit of conductance was mho (℧)(opposite of Ohm, the unit of resistance). The standard unit of conductance is siemens (S). Read More- Go To HOME Page FREQUENCY SPECTRUM OF AMPLITUDE MODULATION (WAVEFORMS AND EQUATIONS DERIVATION)
Electronics is a science that deals with electrical devices and circuits, that operate by controlling the flow of electrons or other electrically charged particles. This branch of science deals with how electrons behave in gases, vacuum or semiconductors. Following are the different branches of Electronics with some details about each branch -
Branches of Electronics
1.Analog electronics
Analogue electronics deals with analogue signals. Analogue signals are continuously variable signals. This is in contrast to the digital signals that generally take only two levels.
2.Digital electronics
The digital electronics deals with digital signals. Digital Signals are the signals that take usually 2 levels.
3.Power electronics
Power Electronics acts as an interface between the electrical source and electrical load. It is the application of solid state electronics to the control and conversion of electric power.
4.Microelectronics
As clear by the name itself, microelectronics is the branch of Electronics that is related to the electronic designs at very small level.
5.Circuit design
The circuit design includes, designing basic electronic components to complex electronic systems.
6.Integrated circuits
Integrated circuits are commonly known as IC in short. An integrated circuit is a small chip that may contain millions of electronic components like resistors, capacitors or transistors.
7.Optoelectronics
As the name suggests, the optoelectronics is the branch of Electronics that combines optics (light) with electronics. It includes the use of light sources, light detectors and mechanism to carry and control light.
8.Embedded systems
Embedded systems are the systems that are designed to perform a fixed function with no or minimum human interference. Embedded systems are controlled by a real time operating system and are the combination of computer hardware and software.
Let's understand what is electronics and the definition of electronics -
Definition of Electronics
Electronics is a science that deals with electrical devices and circuits, that operate by controlling the flow of electrons or other electrically charged particles. This branch of science deals with how electrons behave in gases, vacuum or semiconductors.
Active and Passive Components
Different types of passive electrical components and active electrical components are used in electronics. A passive component is a component that does not produce any energy but consumes energy or is not capable of power gain. Most commonly used passive components in electronics are resistors, capacitors and inductors. If an electronic circuit is completely made up of passive electrical components then it is known as a passive circuit. While active electrical components are the components that are not passive. Common examples of active electrical components are diodes, transistors, silicon controlled rectifiers (SCR) etc. Read More- Go To HOME Page FREQUENCY SPECTRUM OF AMPLITUDE MODULATION (WAVEFORMS AND EQUATIONS DERIVATION)
If x(t) is a signal and we represent its hilbert transform by xh(t), then xh(t) is obtained by providing '-π/2' phase shift to every frequency component present in x(t). Watch the Complete Video Here Now let's see formula to calculate hilbert transform and inverse hilbert transform.
Hilbert Transform Formula
With the help of following formula we can easily calculate the hilbert transform
Inverse Hilbert Transform Formula
The formula provided here can be used to find the inverse hilbert transform
Now let's discuss properties of hilbert transform
Properties of Hilbert Transform
1. A signal x(t) and its hilbert transform xh(t) have the same energy density spectrum. 2. A signal x(t) and it's a hilbert transform xh(t) have the same autocorrelation function 3. A signal x(t) and its hilbert transform xh(t) are mutually orthogonal. We can write it mathematically as-
Carson's formula is used to calculate the bandwidth (BW) of a single tone wideband FM. According to carson's rule, the FM bandwidth is given as, twice the sum of frequency deviation and the highest modulating frequency. But it should be noted here that this rule is just an approximation. Watch the Complete Video Here So Carson's rule can be written mathematically as- BW = 2(∆w + wm) But mf = ∆w/wm Therefore BW = 2(mfwm+ wm) = 2wm (mf + 1) Now we have two special cases for the carson's rule - 1 - If ∆w << wm and 2- ∆w >> wm
Derivation of Carson's Rule for Narrowband FM and Wideband FM
Case 1- If ∆w << wm
Since mf =∆w/wm If ∆w << wm => mf << 1
=> It is the case for narrowband FM Since the bandwidth by the carson's rule is given as- BW = 2(∆w + wm) BW = 2(mfwm+ wm) = 2wm (mf + 1) Therefore for mf << 1 BW = 2wm Note here that this is equivalent to Amplitude Modulation (AM)
Case 2- ∆w >> wm
Since mf = ∆w/wm Therefore if∆w >> wm =>mf >> 1 as is the case for wideband FM Then, since by Carson's rule BW = 2wm (mf + 1) Therefore for mf >> 1 BW = 2wmmf But wmmf =∆w Therefore BW = 2∆w Note- For large values of mf this BW relationship can be considered accurate for all practical purposes. Read More- Go To HOME Page FREQUENCY SPECTRUM OF AMPLITUDE MODULATION (WAVEFORMS AND EQUATIONS DERIVATION)
