The Importance Of Current Sense Resistor In Switch Mode Power Supply

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Current sense resistor is usually located in the switch mode power
supply section. Newer version of monitor-the b+ (boost) circuit
also have this current sense resistor. If you repair electronic
equipment especially the switch mode power supplies, the current
sensing resistor is connected to the source pin of power FET (field
effect transistor) and the other end to HOT GROUND. The value of
current sense resistor is in the range of 0.1 ohm to about 1 ohm.
The values are depends on the design of each power supply.

In monitor power supply where pulse width modulation (pwm) ic UC3842
are used. Pin 3 of this power ic is called I-sense which means
current sense and this pin is connected to source pin of POWER FET.
The purpose of this current sense circuit is for overcurrent protection.
This circuit usually samples the voltage drop across a resistor in series
with the switching fet transistor. If the current rises abnormally due to
some short circuit in the secondary side such as a shorted secondary diode
or horizontal output transistor (HOT), the voltage will exceed a reference
level and shutdown the pulse generator which is the PWM ic. This circuit
provides protection to components in the event a problem occurs.
In some cases where overload happen-the power section will blow and
most of the time the components changed are fuse, power fet, pwm ic,
zener diode and current sense resistor.

Do you know that a small change in this current sense resistor value
have a great impact on the secondary output? A little change in value
say from 0.22 ohm to 0.44 ohm can caused your ouput voltage to drop
into half! I have seen a lot of repairer can't detect this type of
problem (low output voltage) due to that they used analog or digital
meter that don't have the low ohms range. You can't differentiate
if the low ohms resistor has its value changed by using normal meters.
I personally use the Dick Smith ESR Meter which have the capabilities
to check resistor value down to 0.01 ohm! If you don't have this
special meter you may just direct replace the current sense resistor
to see if the generated secondary output will back to normal voltage.

Another tip is that if the current sense resistor in the monitor
B+ circuit have changed value it will caused the output in the
boost circuit to become low and you will have a small width display
and of course the high voltage will become low as well. Instead of
24Kv it becomes 15-18Kv.

Jestine Yong is a electronic repairer and a writer. For more information on electronic repair please visit his website at http://www.noahtec.com/electronic-repair-articles.htm

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5 Reasons Why You Can Make A Lot Of Money With Your Own Internet Radio Station

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Because of these new advances in technology and the availability of sites such as BlogTalkRadio, Speaker.com and uBroadcast, it's now easy, affordable and lucrative to start and run your on web radio station. I can think of many, many reasons why someone would want to start their own online radio station as their primary home based business. However, I'll give you just 5 below which I'm sure will get you thinking.

1. Though starting an online radio station of your own CAN require costly materials such as microphones, mixers, headphones, a station website and server space, there are ways you can eliminate all of these costs and materials. By creating your own online radio show with BlogTalkRadio.com or a comparable platform, you can have your web radio station up and running and earning you money within a matter of hours for free.

2. Once you have your own radio show, celebrities and the rich and famous will tend to seek YOU out! When you're a host of your own radio show, you'll be able to invite all kinds of interesting and well-known people to be on your show. Steve Harrison has a publication RTIR (Radio and TV Interview Report) that you can get signed up for at his web site, and he'll send you contact information on how to get famous guests and writers on your internet radio show.

3. People buy products that are endorsed by the famous and who know famous people! So, imagine that your doing your radio show on the net; You cut for a short commercial break. The music fades out and a wonderful commercial plugs your new ebook, your service, and your name. And voila! Your bank account grows. Because you can utilize celebrity endorsements, you now have greater credibility to sell your products or services on your own radio show.

4. With your own radio show you can use affiliates ads to get companies to send you cheques. It works like this: You join an affiliate program and place banner ads on your website where your radio show is broadcast from. The banners earn you money whenever they're clicked or when the products sell. The affiliate company tracks the click-through from your site by a code put into cookies, and you are mailed a cheque for your commission on the sales. You can also promote affiliate products on your show, giving you an additional way to promote the product and increase your sales.

5. The big money will eventually come from advertising. Now you can, as they say, do the math yourself. If you were on normal radio, it might cost you hundreds of thousands of dollars to find and develop relationships with advertisers, and then create the ads for them. But, by being on the internet, blogging, my-space, and through other PR techniques, you got a good amount of listeners and advertisers will seek you out. And, when you do decide to approach companies with an advertising program proposal, all those listeners you've accumulated will help you impress your prospective advertiser.

So let's look at some numbers. We'll assume for this example that your show is one hour long. Now you're not talking for the whole hour, you're playing music and ads and news pieces in between talking segments. That's where more money comes in for you. You can sell your advertising time for a few dollars. One 60 second spot on one show on the Radio Internet Broadcast Network (RIBN) nationally costs over $1400.00.

So let's say you decide to sell your ad time at RIBN (Radio Internet Broadcast Network) for $600.00 a minute. RIBN puts the ad in for you and you get it all produced with little effort on your part other that finding some advertisers and talking on your show. RIBN gives you 10 minutes for your own ad time on your show. Other companies have other offers and charge more for their show time on the net (some even charge as much as $10,000.00 a show). So to add up your 10 minutes at your price per spot the total is $6,000.00 a show! Now last time I checked there are 52 weeks in a year. 52 times $6,000.00 equals:

That's $312,000.00 a year!

So you see, there are actually hundreds of thousands of reasons to start your own internet radio station:-)

If you take your internet radio business seriously, and if you enjoy music, talking and learning, there could be an amazing future for you in this business. And if you would like more details on the specifics of starting your own internet radio station, I recommend you read Your Internet Radio Station.

Written by T. L. Gillis,

Publisher of WildRose Publishing, 1000 Home Business Ideas and 1000 Ways To Make Money, 1000 Traffic Generation Ideas. Terry L. Gillis is a psychologist, author and entrepreneur who has been advising individuals on business matters for over two decades. If you're thinking of starting a home business, visit 1000 Home Business Ideas for a new home business idea, overview, tips & resources every day.

(c)2011. WildRose Publishing - T.L. Gillis. All Rights Reserved.
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