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Wednesday, October 9, 2019
What is epabx system?
Tuesday, May 3, 2016
Android Mobile Tip : Making lock screen pattern not visible
Making lock screen pattern not visible - If you're annoyed by people looking at your screen every time you draw unlock patten, this may help you.
Setting -> Lock screen.Uncheck -> Make pattern visible
In Setings uncheck 'Make pattern visible'. Next time when you swipe you won't see the lines connecting the dots. Any person watching you unlock will have a hard time figuring out the pattern.
Sunday, March 6, 2016
Why do we use bridge rectifier?
- Bridge rectifier uses less energy.
- Size of a bridge rectifier is lesser compared to a centre tapped transformer type rectifier. Also, since a bridge rectifier contains diodes, it can be embedded.
- The ripple factor in case of a bridge rectifier is lower than compared to the centre tapped transformer type.
- It is easier to maintain than the centre tapped transformer.
By : Rohan-Anand-19
Wednesday, February 17, 2016
Why we use diode for rectification?
In a Rectifier,we are converting the AC into DC,that means from an AC supply we are passing only the positive supply to get a positive dc supply and for that we need a device or a switch which should conduct during the postive half cycle of the AC input only.
Diod is a semiconductor device and only these devices have the property to conduct during the postive biasing.for that reason we are going for diode for rectification.you can also go for Thyristors if you want a controlled DC output as they are also semiconductor devices.
Diod is a semiconductor device and only these devices have the property to conduct during the postive biasing.for that reason we are going for diode for rectification.you can also go for Thyristors if you want a controlled DC output as they are also semiconductor devices.
By : DP-Aurosish
What are the different types of diodes?
Some important diodes and their applications
1. PN Junction diode -
The ordinary diode used in most applications from rectifiers to clippers.
2. Zener diode -
A diode with a high reverse breakdown voltage used as a voltage regulator.
3. Photodiode -
A diode which emits electron hole pairs when exposed to light, used to make detectors and solar cells among other things.
4. Light-Emitting Diode (LED)-
The inverse of the photodiode, it gives out light when driven by electricity. Its low power consumption makes it an attractive lighting source.
5. Tunnel diode -
A diode capable of very high speed operation due to the quantum tunneling effect. It is used in high frequency applications.
6. Varactor diode -
A diode whose capacitance can be varied with applied voltage.
And Finally....
7. Schottky diode -
It is a diode which is used to maintain a fixed voltage of 0.15 - 0.45 Volts. It is used mainly to speed up transistor switching. The Schottky diode has a lower voltage across its terminals when compared to other diodes as it consists of a metal-semiconductor junction as opposed to a P-N junction in others.
It is connected across the base and collector of an npn transistor to maintain a constant voltage (as shown in figure). This prevents the transistor from going into saturation which would slow down switching. These high speed transistors are called Schottky transistors.
The more important point is that the Schottky diode has a lower reverse recovery time compared to the transistor and can switch back faster. Without this feature, the diode would impede the transistor's operation itself. But the Schottky diode enables faster switching as it switches faster than the transistor it is connected to.
1. PN Junction diode -
The ordinary diode used in most applications from rectifiers to clippers.
2. Zener diode -
A diode with a high reverse breakdown voltage used as a voltage regulator.
3. Photodiode -
A diode which emits electron hole pairs when exposed to light, used to make detectors and solar cells among other things.
4. Light-Emitting Diode (LED)-
The inverse of the photodiode, it gives out light when driven by electricity. Its low power consumption makes it an attractive lighting source.
5. Tunnel diode -
A diode capable of very high speed operation due to the quantum tunneling effect. It is used in high frequency applications.
6. Varactor diode -
A diode whose capacitance can be varied with applied voltage.
And Finally....
7. Schottky diode -
It is a diode which is used to maintain a fixed voltage of 0.15 - 0.45 Volts. It is used mainly to speed up transistor switching. The Schottky diode has a lower voltage across its terminals when compared to other diodes as it consists of a metal-semiconductor junction as opposed to a P-N junction in others.
It is connected across the base and collector of an npn transistor to maintain a constant voltage (as shown in figure). This prevents the transistor from going into saturation which would slow down switching. These high speed transistors are called Schottky transistors.
The more important point is that the Schottky diode has a lower reverse recovery time compared to the transistor and can switch back faster. Without this feature, the diode would impede the transistor's operation itself. But the Schottky diode enables faster switching as it switches faster than the transistor it is connected to.
By : Adhithya-K-R
What is the difference between p-n junction diode and tunnel diode?
Tunnel diodes are heavily doped resulting in narrow depletion region hence at less voltage conduction get starts and electrons get easily escaped from at less energy its region while p-n junction diodes are moderately doped
By : Anjali-Rai-15
By : Anjali-Rai-15
What is the difference between a diode and a Zener diode?
Diode
Diode is the simplest semiconductor device and it consists of two semiconductor layers (one P-type and one N-type) connected to each other. Therefore, diode is a PN junction. Diode has two terminals known as the anode (the P-type layer) and cathode (the N-type layer).
Diode allows current to flow through it, only in one direction that is anode to cathode. This direction of current is marked on its symbol with an arrow head. Since diode restricts the current to only one direction, it can be used as a rectifier. The full bridge rectifier circuit, which is made of four diodes can rectify an alternative current (AC) to a direct current (DC).
The diode starts acting as a conductor when a small voltage is applied in the direction of anode to cathode. This voltage drop (known as the forward voltage drop) is always there when a current flow happens. This voltage is usually about 0.7V for normal silicon diodes.
Although, diode allows current flows from anode to cathode, things change when a very large voltage (called breakdown voltage) is applied in the direction of cathode to anode (N to P). In this case, diode is damaged permanently (due to avalanche breakdown) and becomes a conductor allowing a huge cathode to anode current.
Zener Diode
Zener diode is made by doing a little adjustment to a normal diode. As mentioned in previous paragraph, a normal diode will conduct a large reverse current and becomes permanently damaged when a large reverse voltage is applied. Zener diode will also conduct a large reverse current, but the device will not be damaged. This is achieved by changing the way of doping the PN junction and this reverse voltage is called the ‘Zener voltage’.
Therefore, zenor diode can conduct in both ways. If the anode to cathode voltage is higher than forward voltage drop (about 0.7V), it will conduct in forward direction, and it will conduct in reverse direction, if the reverse voltage is equal to zenor voltage (may be any value ex: -12V or -70V).
By : Manish-Agarwal-218
Diode is the simplest semiconductor device and it consists of two semiconductor layers (one P-type and one N-type) connected to each other. Therefore, diode is a PN junction. Diode has two terminals known as the anode (the P-type layer) and cathode (the N-type layer).
Diode allows current to flow through it, only in one direction that is anode to cathode. This direction of current is marked on its symbol with an arrow head. Since diode restricts the current to only one direction, it can be used as a rectifier. The full bridge rectifier circuit, which is made of four diodes can rectify an alternative current (AC) to a direct current (DC).
The diode starts acting as a conductor when a small voltage is applied in the direction of anode to cathode. This voltage drop (known as the forward voltage drop) is always there when a current flow happens. This voltage is usually about 0.7V for normal silicon diodes.
Although, diode allows current flows from anode to cathode, things change when a very large voltage (called breakdown voltage) is applied in the direction of cathode to anode (N to P). In this case, diode is damaged permanently (due to avalanche breakdown) and becomes a conductor allowing a huge cathode to anode current.
Zener Diode
Zener diode is made by doing a little adjustment to a normal diode. As mentioned in previous paragraph, a normal diode will conduct a large reverse current and becomes permanently damaged when a large reverse voltage is applied. Zener diode will also conduct a large reverse current, but the device will not be damaged. This is achieved by changing the way of doping the PN junction and this reverse voltage is called the ‘Zener voltage’.
Therefore, zenor diode can conduct in both ways. If the anode to cathode voltage is higher than forward voltage drop (about 0.7V), it will conduct in forward direction, and it will conduct in reverse direction, if the reverse voltage is equal to zenor voltage (may be any value ex: -12V or -70V).
By : Manish-Agarwal-218
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