Quantcast Figure 3-2B.-Energy diagram for Zener diode

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
3-4 energy difference across this gap determines whether a solid material will act as a conductor, a semiconductor, or an insulator. A conductor is a material in which the forbidden gap is so narrow that it can be considered nonexistent. A semiconductor is a solid that contains a forbidden gap, as shown in figure 3-2, view A. Normally, a semiconductor has no electrons at the conduction band energy level. The energy provided by room temperature heat, however, is enough energy to overcome the binding force of a few valence electrons and to elevate them to the conduction band energy level. The addition of impurities to the semiconductor material increases both the number of free electrons in the conduction band and the number of electrons in the valence band that can be elevated to the conduction band. Insulators are materials in which the forbidden gap is so large that practically no electrons can be given enough energy to cross the gap. Therefore, unless extremely large amounts of heat energy are available, these materials will not conduct electricity. View B of figure 3-2 is an energy diagram of a reverse-biased Zener diode. The energy bands of the P and N materials are naturally at different levels, but reverse bias causes the valence band of the P material to overlap the energy level of the conduction band in the N material. Under this condition, the valence electrons of the P material can cross the extremely thin junction region at the overlap point without acquiring any additional energy. This action is called tunneling. When the breakdown point of the PN junction is reached, large numbers of minority carriers "tunnel" across the junction to form the current that occurs at breakdown. The tunneling phenomenon only takes place in heavily doped diodes such as Zener diodes. Figure 3-2B.-Energy diagram for Zener diode. The second theory of reverse breakdown effect in diodes is known as AVALANCHE breakdown and occurs at reverse voltages beyond 5 volts. This type of breakdown diode has a depletion region that is deliberately made narrower than the depletion region in the normal PN-junction diode, but thicker than that in the Zener-effect diode. The thicker depletion region is achieved by decreasing the doping level from the level used in Zener-effect diodes. The breakdown is at a higher voltage because of the higher


Electrical News
Anatomy of an ARM Server Chip
Four out of the top five server IC companies prefer...
eetimes.com
IoT Gives Old Technology New Life
Cypress Semiconductor sees a great deal of potential for SONOS...
eetimes.com
Andes Ready to Rumble in CPU War
With ARM reigning as king of the CPU IP market...
eetimes.com
D-PHY, M-PHY & C-PHY? First Look at Testing MIPI's Latest PHY
One of the significant advantages of MIPI Alliance standards is...
eetimes.com
Homeless in Silicon Valley
Over Labor Day, I thought about the situation for the...
eetimes.com
Wireless Net Takes the Next Train
The first products are about to adopt the new 802.15.4p...
eetimes.com
EEVblog #659 – Medical Plugpack Teardown
What’s inside an IEC60601-1 medical class 5V mains DC-DC plugpack?...
eevblog.com
Ethernet Links Go Green
Everything that uses energy uses too much if it. Energy...
eetimes.com
Android Wear: Where Are the Wares
Here are examples of some of the watches that use...
eetimes.com
Intel Wearables Contest Goes New Age
Emotional prosthetics, modular smartbands and sixth sense necklaces make up...
eetimes.com
EEVblog #658 – Mailbag
Mailbag Monday. Dave opens his mail Spoilers: Keithley 177 Multimeter...
eevblog.com
EEVblog #657 – Maker Faire 2014 Interviews
Some interviews from the 2014 Sydney Mini Maker Faire at...
eevblog.com
The Internet of Things Versus Slumlords
Smart thermostats are not only for the well-to-do. One group...
eetimes.com
IBM Watson Speeds Drug Research
IBM Watson moves from supplying known answers to tough questions...
eetimes.com
Samsung Funds III-V FinFETs in US Lab
Samsung is funding Penn State researchers working to fabricate III-V...
eetimes.com
LG, Samsung Debut Smartwatches, Apple Lurks
LG's G Watch R and Samsung's Gear S do little...
eetimes.com
Imagination Takes On Raspberry Pi
Imagination Technologies has developed its own version of Raspberry Pi,...
eetimes.com
California Smartphone Kill-Switch Law: What It Means
Do you understand the consequences of California's new smartphone anti-theft...
eetimes.com
9 Insights From Hot Interconnects
Facebook described its network switch, while experts picked apart flaws...
eetimes.com
Microchip in Pursuit of CSR
Microchip confirmed Thursday that it has had preliminary mutual discussions...
eetimes.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +