Now a days we all are familiar with name of battery because every gadget we use, have battery inside from our handset to laptop. The battery can be from  tiny to large as 2 v 2000 ampere cells.

The first device source of power was battery in form of electrical term. Battery was invented before the faraday’s law who invented generator for electrical power.

Battery provide power by conduction +ve ions and -ve ions. these ions flow through the complete path externally by connected wires. That current provide power to any load from lights to motors or any other like electronic circuit board etc.


There is three types of basic battery.

  1. Dry Battery

2.Wet Battery

3.Gel Battery


Dry Battery

                       Dry battery terminology is used for maintenance free battery which are in sealed casing and don’t need any extra work for maintenance. There batteries are mostly rechargeable and can be charged when low in power or voltage. Now a days there batteries are becoming common in wide range of use.


Wet Battery

Wet batteries are also used in some applications. these batteries need special water to be added and maintained at prescribed levels of water.


Gel Battery

Gel batteries are modern form of batteries which are in between dry and wet batteries. This is latest battery technology which are also maintenance free and long lasting.

These kind of batteries are in wide range of industries usage in large power banks. Power banks are becoming common in power plants and most commonly in wind and Solar power Plants. Batteries power banks are also used in thermal, hydel and other kind of power plants for emergency cases.

Combined Cycle Power Plants

The combined cycle power plant is power plant which consists of two power cycles.

i.Brayton Cycle

  1. Rankine Cycle

Brayton Cycle:

In Brayton cycle Gas turbine is powered by gas to spin the generator and produce electrical power. In this cycle Gas turbine also can be power by furnace oil or High speed diesel. The efficiency of brayton cycles gas turbines is up to 40%.


Rankine Cycle:

The other cycle is called HRSG (Heat recovery steam generation). In this process, steam is generated from the exhaust of gas turbine and this is fed to steam turbine to spin the attached generator. The temperature of exhaust is too high near 650c which is enough to generate useable steam. overall efficiency of power plant is increased from 40% to 54%. There are many other accessories for combined cycle power plant which work with parallel as like auxiliary pumps for fuel, water , lube oil, air intake etc.

Details of every cycle is covered in and other article.

Band Pass Filter

Band pass filter is terminology which is used in telecommunication. Filter is device which passes or stops specific things.

 Filter:  Filter is as like net used to catch fishes or birds or beasts etc. Filter is also used for water purification. Here terminology used for filter, is for telecommunication. This filter is electronics circuit which passes or stops the specific frequency.

Band: As written up, here things are discussed are about the telecommunication. Band is range of frequencies. as like from 2 hz to 10 hz. this is called band.

Band Pass Filter: Band pass filter is electronics circuit which pass specific range of frequencies. These filters blocks the specific range frequencies or allow to pass the range of frequencies. When there is modulated signal then for transmission, one of bands or both bands are transmitted. After receiving the signal, for demodulation we have to separate the signal from carrier frequency. Here Band pass or Band stop filters are used. Mostly these filters are used in telecommunication system. Communication system can be of Radio, television, telephone etc

Automatic Transfer Switch

Automatic transfer switch or in short ATS is an electronic circuit which is attached with generator. It operates generator automatically when there is outage of power from the utility. In this circuit there are comparators which look at the line voltage and when the line voltage of utility goes down they switch on the generator and when voltage of generator get stable, they switch on the contactor of main supply to load and thus there is no need for generator operator for all time. Battery is main power source for this panel for operation or self start of generator. The other work it does, is to maintain the voltage level and if the level goes down it cut off the line and starts the generator. This is how Automatic transfer switch work.

Audio frequency

Audio frequency is frequency which can be heard by human or animals. Its range is 4k hz to 20khz. All humans and animal which have audible sound have frequency of voice in this range. The voice, which have more or less frequency than this range it can’t be heard.

In telecommunication transmission is done in high frequencies for fast transmission. These messages or data is then converted to audible frequency for hearing. As like television when its data is transmitted, it is in high frequency but when television set receive and decodes the data and convert it to visible and audible messages. it produces audible message in range these frequencies. So it is called audio frequency.

Apparent power

Apparent power is electrical power summed up of two powers, real power and reactive power. Real power is power which is actually  used by devices , machines, instruments etc in form of heat or magnetic field. it also can be used in other farms as storages like batteries, capacitors, inductors etc.

AC power has two components real power and reactive power. Apparent power is power which appears on the terminal of ac load like motors mostly.  Apparent power is measured in VA,KVA MVA. All the generators are rated in KVA , VA or MVA. Apparent power is sum of reactive and real powers. Reactive power is always present but it is not used. Reactive power is always transmitted back to the system or generator while real power is used by the load. All inductive load or lagging power factor loads transmits reactive power back to the system.

Only resistive load like lights or heaters etc don’t use reactive powers but real power.

In figure you can see the apparent power, real power and reactive power. Real power is also called Active power and True power. Real power is measured in KW and denoted by S. Reactive power is measured in KVAR,VAR,MVAR and denoted by Q

Analog-to-digital converter

Analog to digital converter is electronic circuit which  make analog signal digital. in other words we can say that ADC is basic and very important circuit in modern era of life. when we speak ,microphone  produce analog signal. this signal is then amplified and then before transmission, it is converted to digital form.

Analog signal is continuous signal as like sine wave, sawtooth wave etc while digital signal is discrete signal in the form of 1 and 0. Any of the input or analog signal is converted to digital if transmitted. There are a lot of methods to convert the analog signal into digital form. Mostly used methods are comparators. In comparator one reference voltage is given while on other terminal signal is provided. This comparator gives output if signal voltage is greater or equal to the reference as 1 and 0 vice versa. Here also keep in mind that resolution of digital signal is also important. It mean the signal you are converting into digital form, how many bits signal do you want. one bit, 2 bit,4bit,8bit,16bit  32 bit 64 bit etc. Now a days laptop and window are operation on 64 bit processors.

Amplitude modulation

Modulation is method to impose signal on carrier frequency. There are many methods to do this. Amplitude modulation is one of those methods. In this method signal and carrier frequency are mixed in such a way that amplitude of carrier frequency changes according to signal. This is very old method. In this method there is a lot of noise. in simple it is also called AM modulation. Its range according to other methods is long for transmission but there is lot of noise which is added automatically. It circuit and working is very simple. it is shown in figure.

Keep in mind when amplitude modulation is done there are two signal bands. One upper side band and other lower side band. One of these bands are transmitted some time both of the bands are transmitted and in receiver one band is suppressed and  other is demodulated to get signal. In old system of radio there was AM modulation used. Now it is also used but very rarely.


Its is a process in which components are separate on basis of size ,shape, length, density ( in other words its is a separation process of material).its is a machine which is use in science laboratory such as biotechnology lab.

in this apparatus DNA ,RNA, amino acids and protein are separated by plant or animals cell or tissue (bacterial genetic material also be separated).


Its works on density of components desire to separate in form of homogeneous solution


F=intensity of centrifugal force

M= Mass of particle

w= angular volecity of rotation

r=distance of migrating particle from center of axis of rotation

Types of Centrifuge:

1.small bench top centrifuge:

a).in this centrifuge without chill solution can be separated.

b).blood ,serum .etc are separated

c).slow in speed upto 4000 rpm

d).100 eppnodroff tube are can be  loaded in a time.


2.Micro Centrifuge:

a).2mm volume of eppnodroff tube

b).10,000 eppnodroff tube can be loaded

c).protein are separated

3.High speed centrifuge:

a).50,000 eppnodroff tube are loaded

b).sub.organelles are separated

c).17000 rpm speed

4.ultra high speed centrifuge:

a).90,000 eppnodroff tube are loaded.


b).chilled material are used

c).microorganisms are separated

  • Rotar in centrifuge
  • Fixed rotar

horizontal solution are in rotation and clearly pellets are separated debris are obtain

  • swimming bucket rotar

its solution in vertical position in rotation and no clearly pellets are separated

Power Amps:

Power Amplifier is electronics circuit which amplify the signal. In other words amplifier is circuit or electronic device which make week signal strong. Amplifier is an essential part of mostly used devices like, mobile , Television, Audio amplifier, CD players, tape recorders etc. In other words amplifier is important part of any system, transmission system or any other. The main        part of the amplifier is transistor an electronics  component which amplify the signal. any signal which is amplified in micro volt or amps and output is in few amps. It is said that amplifiers can amplify signal up to 1000s of times, it is true. but keep in mind it cannot be 1 volt to 1000 volt but it can be from 1u volt to 1 volt which is million times amplified.

How Amplifier works:

The working of amplifier is as we week signal is applied on the base of the transistor it makes changes in current or voltage flowing from emitter to collector of transistor. Thus voltage measure on the resistor which is connected at collector in series, is high. it is called that signal applied on base of transistor is amplified. The value of resistor in series with collector is always high rather than resistance of emitter. These resistances actually cause amplification of signal. look at figure: