Saturday, October 30, 2010
Thursday, October 21, 2010
Amateur radio also called ham radio is an awesome hobby and lots of fun. If you are already into electronics and enjoy studying radio theory than this is most likely a hobby you would really enjoy. Preher-Tech has added an amateur radio page to our website that includes basic info on amateur radio as well as a list of all the books you will need to get started in this hobby. I myself am a general class operator, my call sign is KF7LTV
and I am planning to go get my amateur extra license very soon, giving me full privileges on the amateur bands. Hope to hear some of you on the air soon. Click here to visit our amateur radio page.
Don't forget to visit www.preher-tech.com for all your electronics needs.
Tuesday, October 19, 2010
Electrolytic capacitors are capable of providing the highest capacitance values of any type of capacitor. However they have drawbacks which limit their use. The voltage applied to them must be polarized; one specified terminal must always have positive potential with respect to the other. Therefore they cannot be used with AC signals without a DC bias. They also have very low breakdown voltage, higher leakage current and inductance, poorer tolerances and temperature range, and shorter lifetimes compared to other types of capacitors.
Sunday, October 17, 2010
•Are you afraid to work on laptops for fear of breaking them?
•Do you want to expand your skill set so you can make big money fixing laptops instead of sending the business away?
•Receive the same high level of Podnutz quality, as Steve releases the long awaited Laptop Repair Video Collection!
What do you get in this package? You'll see in full 960x540 HD video:
•How to replace a motherboard
•How to replace an LCD Screen
•What to do when the laptop keeps shutting down
•How to fix DC power jacks
•The crucial difference between a bad screen and a bad inverter board
•How to replace hinges
•Where I buy all my parts
•The best way to go about taking a laptop apart
•How to solder
•The art of fixing AC adapters
•How to handle a laptop that has had liquid spilled in it
•what to do when a laptop overheats
•how to replace CD/DVD drives, RAM, processors, hard Drives and wireless cards
•and much, much more!!
Tuesday, October 12, 2010
Wednesday, October 6, 2010
Tuesday, October 5, 2010
An opto-isolator also called an opto-coupler or photo-coupler allows a signal to pass from one circuit to another but allows the two circuits to remain electrically isolated. The most common opto-isolator which comes in IC package consists of an LED which shines onto the base of a photo-transistor (usually an npn transistor) and allows current to flow from collector to emitter until the LED is turned off. When a signal is applied to the LED it then shines light that is varied in brightness with the same amplitude as the input signal, this light lands upon the photo-transistor (the resistance of the collector/emitter junction now changes with the varying light) which passes the signal onto the next circuit.
Basic opto-isolator symbol.
If you do a lot of work on switch mode power supplies than you have surely seen the opto-isolators used in the feed back section of the power supply.
Opto-isolators in LCD TV SMPS.
If you want to read more about opto-isolators including my 3 methods for testing them than dowload my free article "Understanding and Testing Opto-isolators" by clicking here.
Included in the article is a schematic and parts list for a simple opto-isolator tester.
Don't forget to visit http://www.preher-tech.com and also if you have any electronics related questions you can email me firstname.lastname@example.org for assistance.
Recommended Repair Guides:
LCD TV Repair Guide
LCD TV Repair Case Histories