Introduction to Using Zener Diodes As Voltage References

Zener (a.ka. avalanche or breakdown) diodes are p-n junction semiconductor devices designed to operate in the reverse breakdown region of their VI characteristic curve. By maintaining their reverse current within certain limits, the voltage drop across the diode will remain constant. If maintained in this mode of operation, the diode will act as a voltage reference.

Examine the spec sheet for a typically avalanche diode – Vz is the Zener voltage measured at a given test current Izt. The knee current Izk, is the minimum current through the device to maintain a constant Vz. Since the dynamic resistance at the knee of the of the response curve is high, if current through the device is below Izk, regulation will be poor. Izm is the maximum Zener current that can be passed without exceeding the maximum permissible power dissipation. Violate this and the device will turn into smoke before your eyes.

For operation as a voltage reference, a Zener diode must be reverse biased. When the reverse voltage is smaller than Vz only the normal diode reverse saturation current is allowed to flow. high voltage diode When forward biased it behaves like an ordinary silicon diode – a large forward current flows, and the forward diode voltage is typically 0.7 V. Avalanche diodes are available with maintaining voltages from several voltages to several hundreds volts and with power dissipation ratings up to 50 Watts.

The temperature sensitivity of a Zener diode (temperature coefficient) is given as a percentage change in reference voltage per centigrade degree change in diode temperature. This number is usually in the range of +/- 0.1 percent per deg C. The direction of the change is related to the mechanism of breakdown (avalanche multiplication versus Zener breakdown). Generally, if the reference voltage is above 6V the coefficient is positive, if below, negative. Some manufacturers have produced temperature compensated reference diodes by combining a positive temperature coefficient breakdown diode with a forward biased, negative temperature coefficient, silicon diode in a single package (i.e. the generic 1N829, a 6.2V reference diode with a temperature coefficient of +/- 0.0005 % per deg C over a range of -55 to +100 deg C). Rather than use a single larger diode it is often better to place multiple breakdown diodes in series when designing a high voltage reference. This combination allows higher voltage, higher power dissipation, lower temperature coefficient, and lower dynamic resistance (the reciprocal slope of the volt-amp curve in the operating region). Of course, this is a more costly solution than a single diode.

Parents Protect Their Children With Web Monitoring Software

With the worldwide web so easily accessible, more and more parents are searching for web monitoring software to help them keep their children safe. They are hoping that these programs will help them to better monitor what is going on in their child’s online lives. The following article will discuss the subject further.

Parents are finding thousand and thousands of downloads on the internet for computer monitoring software. Once you find a program they are comfortable with, it should be installed on the machine your children use the most. Once it is installed, the program will record each stroke your child makes from his keyboard, including passwords, email addresses, and chat logs. Anything your child types will be recorded and put in a log for you to read later.

With most web monitoring programs, the log of the activity will be encrypted so you child will not be able to recognize it. And in cases where you child may be computer savvy, the log file can be password protected in addition to being encrypted. There is no way your child can get to the log file. threat intelligence solutions Tampering with the log will be impossible for them to do.

The worldwide web is full of millions of keylogger programs to choose from. Some of the programs offer their services free, while some of them require purchase. Free programs are often effective in logging each key stroke made, but the paid programs are less likely to be detected by your child.

Free web monitoring software can often be detected by any virus program that is run on the machine. The software will most often be listed as a virus, although it is not. The monitoring software you pay for cannot be detected at all by a virus scan or spyware scan. Additionally, most of the free services are often listed in the task manager box, should your child bring up the task manager. This is not the case when you pay for your software. Most programs you pay for are totally undetectable.

As parents, it is our natural instinct to do whatever it takes to protect our children. While the internet is full of useful information you child may need to access in order to better their education, there are also dangers associated with it. By monitoring your child’s online activity with software programs, you are only trying to prevent them from encountering the dangers.

Tips To Create A Great Whatsapp Status

Whatsapp is a messenger application that has become very popular not just amongst youngsters but also amongst adults because it makes it easy for people to chat and keep in touch. Perhaps the major reason as to why this mobile platform is loved is because messages can be exchanged across all operating systems and all mobile phones. It is also a platform that uses the normal data plan for email and browsing the internet and therefore does not add any extra costs to chat, share videos and audio messages with friends and family.

Your Whatsapp status is very important because it easily tells your friends what is on your mind or your mood. You can actually use the status to let people know how you are feeling without talking to them. Those in your list of contacts will frequently be checking your status and your profile photo and they therefore can tell exactly what is going on in your life. It is good to have a cool status, but you also should pay attention to what you are posting, however free you are to post anything on your profile.

Be clear and concise – Short but clear messages can be lovely because they are easy for people to understand what your feelings are. Short statuses are loved because they do not take much time of whoever comes across them. Think about what you want to say and find a sentence that can summarize Fmwhatsapp it so you do not end up writing a story.

Keep your readers guessing – Another way of achieving a great status is to keep the status twisted in such a way that readers are not too sure what you could be saying. A status sentence that has a deeper meaning that is not that easy to unveil can keep your friends wondering what you could be talking about or what you are up to. You can be as creative as you want to be when creating such a status to keep the interest and suspense of your circle of friends.

Use inspirational messages – They are great because they actually can work as a motivator to contacts who could be feeling low or sad about an aspect of life. You can choose sayings that have deep meanings or come up with your own creation of a message that is bound to inspire others. You can never know how many situations you can change for others when you select a meaningful status.

Vent but don’t mention any names – Unless you are writing a positive status dedicated to a person you want to appreciate, avoid mentioning names. It is okay to be mad and angry at someone, but quite another when you put it across for everyone else to see. Find a friendly way of venting your anger without compromising the identity of the other person. You should actually think twice about hurling insults at a specific person using your status. It’s good to keep things civil and find ways of settling the situation directly with the person involved.