Showing posts with label Electronic Knowledge. Show all posts
Monday, November 9, 2020
TRANSISTORS AS A SWITCH
Transistors
In 1947,The world of electronic devices is completely changed by the two physicists
John Bardeen and Walter Brattain when they made the first working device on point contact transistor.
Transistor are the semiconductor device having three terminals, used as a switch or to amplify a current. They are very light in weight around 1gram or less and very small in size. The phone that you are carrying is light in weight and have small size that fit in your hand because of the transistors.
Transistors can used as a switch in digital electronics and as an amplifier in the analog electronics.
Transistors have 3 terminal:
1.Emitter
2.Base
3.Collector
Emitter is the source of charge carrier and that is why it is heavily doped.
Base is lightly doped and very thin in size
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| Transistor |
Active region:
When the base emitter region is forward bias and collector and base region is reversed bias.
For this condition :
Base voltage must be higher than emitter voltage and Vbe =0.7 Volts
Collector voltage must be higher than base voltage so than collector voltage is higher than the other region voltage.
The base current is directly proportional to the collector current.
Transistor act as a switch:
Transistor can act as a solid state switch that doesn't require any moving part, it act as a on/off switch just by sending a base signal.
For transistor to act as a switch:
- Emitter is connected to the Ground.
- Base is connected to the on/off signal with a resistor
- Collector is connected to the 5v supply.
When a base current is flow through the transistor. So, it will create a path for the Emitter electron to flow through base region to the collector region and the current will easily flow through the collector region to the emitter region and act as a short circuit path. Transistor act as ON switch.
When base current is remove the collector current can't cross the base region and act as a open circuit or OFF switch.
So, in this way transistor can act as a switch
Friday, October 2, 2020
Capacitor
Electrolytic capacitor:
Electrolytic capacitor uses electrolyte to achieve large value of capacitance than the other capacitor types.
Electrolytic capacitor always connected in forward bias ie Anode voltage must be in higher voltage than the cathode voltage. If it is connected in reversed bias it act as a short circuit
Application :
It is used power supply as a filtrating devices to reduce the ripple in voltage.
And
In the low pass filter for the input and output smoothing and doesn't work in large amplitude and high frequency signal.
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| Electrolytic Capacitor |
Capacitance:
Capacitance is the measurement of charge stored in the capacitor. Farad is the S.I. unit of capacitance.
We generally, don't use 1 farad of capacitance because 1 farad is a huge value of capacitance, if we want to make a 1 Farad capacitor, it will occupy a half space in your room.
However, we uses very less power capacitance for household purposes. Generally we uses 2.25 microfarad capacitor in our 220v Fan and all our tv, computer and laptop have capacitor have capacitor which have value:1*10-12.
Ceramic Capacitor:
Ceramic capacitor is a fixed value capacitor which is made up of ceramic dielectric that's why gets the name: ceramic capacitor. Ceramic capacitor are small in size and are in the range of few picofarad to microfarad. These are used for coupling and decoupling applications.
Saturday, May 16, 2020
Sensor and Transducer
Transducer:
Transducer is a device that converts one form of signal into the other form of signal.
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| Transducer |
The input is given to the Sensor and the output of sensor is the input of Processor.The combine process of sensor and processor is a Transducer in which the sensor converts the physical quantity into electrical signal and processor continue the further process.
Now the Processor output electrical signal is given to the Actuator which coverts the electrical signal to the mechanical works,which is also an example of transducer.
Examples:
Microphone: Convert voice to Electrical signal
Speaker: Convert Electrical signal into Sound
Antenna: Converts Electromagnetic energy into electrical and vice versa
Strain Gauge : Convert strain to electrical. Strain gauge is a sensor that converts strain(Force) into the electrical signal,its resistance changes with the applied force on it and force magnitude can be easily measured.
Sensor:
Sensor is a device that converts physical quantity into electrical signal.
Example: Temperature and humidity sensor- DH22,
PIR Sensor: Passive Infrared Sensor is an Electronic device that measures infrared light radiation emitting from the object in its range.Generally, PIR can detect any Human/Animal movement in a range,the sensor doesn't emit any energy but passively receives and detect infrared energy from the environment.
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| PIR Sensor |
Ultrasonic Sensor: It is an optical sensor and can detect how far an particular object is placed.It uses a transducer to send and receive ultrasonic sound waves that gives an approximation distance of the object from the sensor.
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| Ultrasonic Sensor |
LDR Sensor :Light Dependent Resistor has a variable resistance which is the function of intensity of light falls on the surface of sensor. Its resistance decrease with the increase in the intensity of light falling on it. LDR can be used in the street light to automatically switchs on and off the lights when it requires.
LED: Led is a semiconductor which emit lights when current flows through it.
Led has two terminal:
Anode which is long terminal and positive in nature.
Cathode which is short and negative in nature.
Current aways flows from the anode to Cathode in LED and never in the opposite terminal.
The operating voltage of LED is around 1.8 to 3.3 volts it varies by the color of LED.Current varies from 10mA to 20mA which maximum current capacity of LED. It will burn out, if current more than 20mA goes in the LED.
Always, a Resistor is connected in series with LED to limit the current through the LED. The resister used is known as ballast resistor
Sunday, January 20, 2019
Amazon Echo -Changing future of speaker
Amazon Echo is not just a cylindrical who listen to your command and responds to it. It is a smart intelligent speaker which will be in every home in the world within in a few years. Every home feels the requirement of such a smart speaker like Amazon Echo.
On 23 June 2015, Amazon launch th amazon Echo only to the prime member and after a year on 28 September, 2016 is available for the rest of the world. It is a voice control smart speaker with Bluetooth and wifi connectivity. It is 9.5 inches tall cylindrical speaker with 7 piece microphone, ARM Cortex-A8 processor,256 Mb of LPDDR1 RAM and 4Gb of storage space.
Alexa is a voice assistant who responds to your commands in a sweet voice. You simply sit on the sofa and commands to Alexa for setting an alarm to searching the web to answer your question and play your favourite music.
Alexa have the ability to turn the devices on and off. All you need is a smart bulb and plug which can be controlled with your voice which is very useful to those who kept the device on after using it. It is useful in saving the electricity which nowadays is a very serious problem for the planet Earth.
Hope you it.share your veiws in comments
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On 23 June 2015, Amazon launch th amazon Echo only to the prime member and after a year on 28 September, 2016 is available for the rest of the world. It is a voice control smart speaker with Bluetooth and wifi connectivity. It is 9.5 inches tall cylindrical speaker with 7 piece microphone, ARM Cortex-A8 processor,256 Mb of LPDDR1 RAM and 4Gb of storage space.
Alexa is a voice assistant who responds to your commands in a sweet voice. You simply sit on the sofa and commands to Alexa for setting an alarm to searching the web to answer your question and play your favourite music.
Alexa have the ability to turn the devices on and off. All you need is a smart bulb and plug which can be controlled with your voice which is very useful to those who kept the device on after using it. It is useful in saving the electricity which nowadays is a very serious problem for the planet Earth.
Hope you it.share your veiws in comments
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