Quantcast
FORWARD BIAS - 14179_32

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
1-20 charged ions. The diffusion of electrons and holes across the junction will continue until the magnitude of the electrostatic field is increased to the point where the electrons and holes no longer have enough energy to overcome it, and are repelled by the negative and positive ions respectively. At this point equilibrium is established and, for all practical purposes, the movement of carriers across the junction ceases. For this reason, the electrostatic field created by the positive and negative ions in the depletion region is called a barrier. Figure 1-17.—The PN junction barrier formation. The action just described occurs almost instantly when the junction is formed. Only the carriers in the immediate vicinity of the junction are affected. The carriers throughout the remainder of the N and P material are relatively undisturbed and remain in a balanced condition. FORWARD BIAS.—An external voltage applied to a PN junction is call BIAS. If, for example, a battery is used to supply bias to a PN junction and is connected so that its voltage opposes the junction field, it will reduce the junction barrier and, therefore, aid current flow through the junction. This type of bias is known as forward bias, and it causes the junction to offer only minimum resistance to the flow of current. Forward bias is illustrated in figure 1-18. Notice the positive terminal of the bias battery is connected to the P-type material and the negative terminal of the battery is connected to the N-type material. The positive potential repels holes toward the junction where they neutralize some of the negative ions. At the same time the negative potential repels electrons toward the junction where they neutralize some of the positive ions. Since ions on both sides of the barrier are being neutralized, the width of the barrier decreases. Thus, the effect of the battery voltage in the forward-bias direction is to reduce the barrier potential across the junction and to allow majority carriers to cross the junction. Current flow in the forward-biased PN junction is relatively simple. An electron leaves the negative terminal of the battery and moves to the terminal of the N-type material. It enters the N material, where it is the majority carrier and moves to the edge of the junction barrier. Because of forward bias, the barrier offers less opposition to the electron and it will pass through the depletion region into the P-type material. The electron loses energy in overcoming the opposition of the junction barrier, and upon entering the P material, combines with a hole. The hole was produced when an electron was extracted from the P material by the positive potential of the battery. The created hole moves through the P material toward the junction where it combines with an electron.


Electrical News
Bagels: Official Food of Test & Measurement
A bagel is the perfect food to eat at your...
eetimes.com
Max's BADASS Display, Part 3
Now we come to consider the various ways in which...
eetimes.com
Smartphones, 28nm Tech Drive TSMC 1Q Revenue
Thanks to demand for high-end smartphones and investment in technology...
eetimes.com
Quantenna Speeds Up WiFi
As several major companies roll out 802.11ac solutions with multi-user,...
eetimes.com
Samsung Patent Leaks Point to Google Glass Competitor
In a series of leaked patent documents from South Korea,...
eetimes.com
IMEC Adds Image Sensors to Commercial Development Service
The Belgian company has published a brochure that boasts of...
eetimes.com
Why iBeacon Is Important for You
It's true that iBeacon may help you find a restaurant...
eetimes.com
Sensors Combat Corrosion
The energy Piplines Cooperative Research Centre and Deakin University (Australia)...
eetimes.com
Power Week-in-Review: Wristband TE Generator & Solar Cell Efficiency Record
This week, a flexible band-shaped thermoelectric generator that can harvest...
eetimes.com
A Picture Is Worth 1000 Words - So Add One to Your Profile Already!
My personal preference is that I like to know who...
eetimes.com
NASA Tests Technologies for Deep Space Exploration
An oxygen recycling system, optical communications, and a deep space...
eetimes.com
DARPA Turning Drones Into WiFi Hotspots
The US military's research division is equipping aging drones used...
eetimes.com
ON Semi on a Roll With Image Sensors
Coupled with the company's acquisition of Truesense last week and...
eetimes.com
Wearable Computing Market on 78% CAGR Through 2018
By the end of 2014, shipments of wearable devices are...
eetimes.com
EEVblog Server Issues
The EEVblog dedicated server which hosts this site and the...
eevblog.com
EEVblog #604 – Sinclair C5 Restoration – Part 1
The obligatory “before” video showing Dave’s Sinclair C5 electric “car”...
eevblog.com
Samsung, Glofo Roll 14nm Process
Putting heat on TSMC, Samsung and Globalfoundries are putting a...
eetimes.com
The Big Fat Indian Election
Technology and data analysis have come to play a crucial...
eetimes.com
Are PCB Layout Designers an Endangered Species?
Are PCB layout designers as a group poised to fade...
eetimes.com
Motorola People, Products Remembered
As some of the last big chunks of Motorola going...
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 +