Thursday, January 27, 2011

How to Protect Your Electronics From Heat

1.0 INTRODUCTION
In our modern society, we have become very dependent upon our electronic gadgets and appliances. Most households (in the U.S) have Personal Computers with an Internet Connection. If we solely looked at the Personal Computer, we do a lot of thing with this product.
  • We communicate with our friends, family members and business associates.
  • We conduct financial transactions (e.g., buy or sell products on line)
  • We create all kinds of documents (which are very important to our personal and business finances/operations)
  • We store and play music (in the form of *.mp3 files)
  • We (increasingly) store pictures that have sentimental value (and could be tough to replace if lost).
For many people, anytime their "computer dies", it becomes a major inconvenience in their lives. If you were to look at some other electronic systems that we typically have in our homes, such as
  • DVD Players
  • Gaming Systems (e.g., Playstation, X-Box, Nintendo, Wii, etc.)
  • Audio Entertainment Equipment
  • Video Recording Equipment (for you people that like to post videos on YouTube.
  • Appliances (such as Central Air Conditioning Systems, Heat Pumps, Microwave Ovens, etc.)
  • HDTVs (e.g., LCD or Plasma)
All of these items entertain us, enlighten us and provide us with comfort. These products each require a considerable amount of money to purchase. Further, repairing and/or replacing these products is also quite expensive. Hence, I am quite amazed that people do not do more to protect their investment (in these electronic systems) and do whatever they can to extend the operating life time of these products.
In general, there are three (3) different destructive mechanisms that will either destroy or greatly reduce the operational life-time of your electronics. These three destructive mechanisms are
  • Heat
  • Electrical Surge/Spike Events, and
  • Electrical Noise
In this article, we are going to talk about HEAT. As we discuss Heat, we will cover the following topics.
  • How is Heat destructive to your electronics?
  • What can we do about heat - How to Protect Your Electronics from Heat and Extend the Operating Life of our Electronics?
2.0 HOW IS HEAT DESTRUCTIVE TO YOUR ELECTRONICS
Heat is an artifact of electronics. All electronic systems generate heat. Electronic systems accept electrical power (current and voltage) from the power line (via the electrical outlet). The electronic system uses a portion of this electrical power to perform work (e.g., the function that you want it to perform, e.g., play a DVD, cook a bag of popcorn, etc). The remaining portion of this electrical power is converted into heat.
However, heat is also an enemy of electronic systems. Few things are more effective in reducing the operating life-time of an electronic system, than raising the operating temperature of the electronic circuitry within your electronic system. If you were to speak with an Electronics Device Reliability expert, he/she would tell you that for every 10 degrees (Celsius) that you raise the operating temperature of an electrical device; you reduce the operating lifetime of that device by 50%. The impact of heat (in shortening the operating life) of your electronics is "huge".
3.0 WHAT CAN WE DO ABOUT HEAT?
As I mentioned earlier, all electronics generates heat. There is no way to prevent electronics from generating the very thing that can destroy it. However, there are a couple of things that you can do to prevent this heat from doing so much damage.
1. You can work to remove this heat from the electronics (as quickly as it generates it), or
2. You can do things to try to help the electronics to not generate so much heat in the first place.
I will address each of these approaches below.
3.1. REMOVING HEAT FROM THE ELECTRONICS
Many consumer electronic systems were designed with "Heat Removal" in mind. Some of these electronic systems (like desktop computers) contain "internal fans". These fans were designed into these systems so that they could blow air through the area in which the system electronics resides. The intent behind having these fans to is blow the heat away from these electronics and to help keep them cool.
Other electronic systems contain "vents" (in their outer case) to provide an "escape path" for heat. Many of these vents are located at the top or in the "back-end" of the electrical system. On this basis, I have the following recommendations to permit the removal of heat from your electronics.
Make sure and keep papers, books, dust and other items from "blocking" the vents of these systems.
Leaving these items on top of your (DVD Player for example) will block the vents, and will not allow for heat to escape from your DVD Player. This will cause the temperature (surrounding the electronics) within your DVD player to rise; which will (in-turn) reduce the operating lifetime of your DVD player.
Make sure that the "back-end" of the electronic system is not "butt-up" against the wall or an entertainment cabinet.
It is important to make sure that there is sufficient air/ventilation space between the vents (in the back end) and the wall/cabinet to allow for Heat Removal.
Make sure and have your appliances (like your Central Air Conditioning system or Heat Pump) serviced.
Whenever these appliances are serviced, the service professional will do various things (like clean out dust and debris from ventilation path), therefore maintaining an unobstructed path for heat to escape from these systems.
Make sure that the fan (inside some of your systems) is working.
If this fan stops working, then you need to get it repaired quickly. Failure to do this will result in your electronic system having an early meeting with the "grim reaper" or an electronic waste disposal site.
3.2 REDUCE THE AMOUNT OF HEAT THAT THE ELECTRONICS GENERATE IN THE FIRST PLACE
Another approach to protecting your electronics from heat is to take steps to try to prevent your electronics from generating excessive heat in the first place. The amount of heat that is generated within an electronic system is often referred to as being related to the following expression for resistive loss: I^2XR, where:
  • I represents the amount of current flowing through an electronic system and
  • R represents the load impedance (or resistance) within this electronic system; and
  • I^2 denotes " I being raised to the 2nd Power, or "I-squared"
From this mathematical expression, you can see that if we were able to reduce the amount of current flowing through an electrical system, this would certainly help to reduce the amount of heat generated within this electrical system.
QUESTION: How can you reduce the current that an electrical system uses? Doesn't it require a certain amount of current to do its job? The answer to this question is "Yes", an electrical system does require a certain amount of current and voltage (electrical power) to do its job. However, it doesn't need to use anymore current than that. Hence, we recommend that you use TVSS (Transient Voltage Surge Suppressors) components in order to reduce the current level (flowing into your electrical system).
Now, I know that some of you may be "scratching your heads" and wondering, "How in the world will this reduce the amount of current flowing into my electronic system" and (in turn reduce the amount of heat that it generates)? The answer is this: Anytime there is a large amount of electrical noise or spikes, or other forms of distortion in the electrical voltage and current in the power line, this also results in the flow of additional current into your electrical system. By using the TVSS components, you are eliminating this excessive current (due to noise, glitches, etc.) from the "power line" current, flowing into your electronic system.
In this case, you have now accomplished the following:
1. You have decreased the amount of current flowing into your electronic system, (which is the "I" in the expression "I^2 X R") - which helps a lot to reduce the amount of heat that the system generates.
2. By reducing the heat that the electrical system generates, you are now lowering the ambient (or surrounding) temperature in which your electronics operates.
3. Lowering the ambient temperature will often times also reduce the load impedance/resistance in your electronic system (e.g., the "R" in this expression) as well.
QUESTION: How can you reduce the load impedance/resistance in an electronic system? Isn't that a design feature of the electronic system? The answer to this question is "Yes it is". You cannot change the load impedance/resistance by very much. But, the reason why lowering the ambient temperature will also reduce the load impedance/resistance is that many resistors have (what is called) a positive temperature coefficient. This means that as the ambient temperature goes up, does the resistor value of this particular resistor.
However, the converse is also true. If you were to lower the ambient (or surrounding) temperature, then you would also lower the resistor value as well.
SO LET'S RECAP THE BENEFITS OF USING TVSS COMPONENTS:
  • Using TVSS components lower the amount of current flowing through your electronic system.
  • Lowering this current reduces the amount of heat that the electronic system generates.
  • This lowers the ambient temperature for the system electronics.
  • Lowering the ambient temperature also lowers the load impedance/resistance (R) within the electronic system.
Both the reduction of current (and the resulting reduction of the load impedance) would serve to significantly reduce the amount of heat that the electronics system will generates.
4.0 OTHER ARTICLES IN THIS SERIES
Other articles in this series are listed below.
  • How to Protect Your Electronics from Electrical Surge/Spike Events
  • How to Protect Your Electronics from Electrical Noise
5.0 CONCLUSIONS
In this article, we spoke about "heat" and how effective it is in reducing the operating life-time of your electronics. Heat is one of the three (3) destructive mechanisms that will either destroy or shorten the operational life-time of your electronics. The remaining two mechanisms are
  • Electrical Surge/Spike Events, and
  • Electrical Noise
We have also described some guidelines on how to protect your electronics from heat, and to extend the operating life-time of your electronics. In particular, we mentioned the following approaches:
1. Use (and do not thwart) the "Heat Removal" features of your electronic systems
  • Make sure that Internal Fans are working and
  • Make sure that vents are not blocks and that there is plenty of air space around the Electronic system to allow for the escape of heat.

2. Use TVSS (Transient Voltage Surge Suppressor) components to regulate the amount of voltage (and in turn) current that is flowing into your electronic systems: Minimizes heat generation due to resistive loss.
Do you wish to learn more about approaches to protect your electronics from the affects of heat, electrical surge events and electrical noise?
Click here to learn more about an approach to protect your electronics from all three of these destructive mechanisms and extend the operating life of your electronics.
Darrell E. Smith has more than 25 years of experience as an Electrical Engineer. He is also an experienced Article Marketer and a Distributor for a Company that Manufacturer's "Healthy Living/Green Technology Products".

Tuesday, March 16, 2010

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published: Aug 11, 2008



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How 2.0: Make a Solar Cell Phone Charger

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From http://www.2pointhome.com



A little soldering is all it takes to make this cool little emergency cell phone charger. Keep it in the glove box of your car, in case you ever get stranded in the woods and start to hear banjo music!



You might be able to find the mini solar panels at a store that sells science or electronics equipment; otherwise you can order them online. Please note, you'll also be cutting the wire on the cell phone charger, so make sure it's not the only one you have! You can often find cheap chargers at discount stores like Big Lots -- it doesn't matter if it's AC or car compatible, since you'll only be using the end that plugs in your phone.



MATERIALS:



1 Altoids Tin case

2 Mini Solar Panels (3V 20mA each)

1 Solder (3")

1 Small Heat Shrink Tubing (4")

1 Large Heat Shrink Tubing (4")

1 Double Sided Tape (3")

1oz Flux

1 Solder Iron

1 Heat Gun

1 Wire Stripper

1 cell phone charger





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step 1Step1: Cut wires & tubing

Take the 2 solar power panels and cut all four wires to about 1" in length. Cut 1/4" of plastic off of the tip of each wire with the wire stripper so copper wires are exposed. This exposed wire is called a 'lead.' Cut the small heat shrink tubing into four equal pieces (1" each). Slide the small heat shrink tubing onto both black wires.





step 2Step 2: Solder solar panel leads

Using a toothpick, paint leads with flux on a red wire from one solar panel, and a black wire from the other solar panel. Put those two leads together, and solder using your piece of solder and the soldering iron.





step 3Step 3: Heat-shrink tubing

Slide small heat shrink tubing over the leads you just soldered together. Heat the tubing with heat gun just enough for it to shrink.





step 4Step 4: Cut phone charger wire

Cut off the wire from your old charger to about 2.5 feet and strip off 2.5" of outer plastic from the loose end. Cut 1/4" off of each of the inside wires to make leads. Slide the full length of the large heat shrink tubing onto this main wire for later use in Step 6





step 5Step 5: Flux, solder and heat-shrink loose leads

On your main wire, slide a piece of small heat shrink tubing onto the red wire. Flux all loose leads of main wire as well as the solar panels with the toothpick. Solder red leads from main wire and solar panels together. Repeat with black wires. Slide heat shrink tubings over these soldered leads and use heat gun to shrink.





step 6Step 6: Test charger

Test the charger by connecting it to a phone under bright light.





step 7Step 7: Heat-shrink solar panel leads

On your main wire, slide large heat shrink tubing over the two soldered leads which connect to the solar panels. Use the heat gun to shrink the tubing.





step 8Step 8: Tape and close

On the back of the solar panels, cover the two brass rivets with double-sided tape (so they don't make contact with the Altoids tin.) Tape the two solar panels on the inside lid of the tin. Tuck the main wire into the case and close. Go somewhere sunny (Florida is nice) and charge it up! For more great DIY projects visit: http://www.2pointhome.com





27 comments Add Comment









Feb 14, 2010. 2:23 PMdeathpod says:

can a led work in place of a more orthodox diode?



REPLY







Dec 3, 2009. 7:25 PMmike_k11 says:

But if i put a multi charger instead of my cell phone cable ?...how can i chose a time 1/2, 1 or 2 hours switch ? and nothing else



Thanx



REPLY







Dec 3, 2009. 8:49 AMRick_Covert says:

A polarity protecting diode should be a MUST when working with a project of this type for safety reasons and to protect the phone. Everyone makes mistakes and it would be tragic to loose a free or $40 pluse phone over something as careless as reversing the polarity of an under $10 solar charger. However the other posters have made valid points about the rather harsh voltage drop of .7 volts for using these diodes. Therefore I recommend the use of Schottky diodes which only exact a .2 volt drop penalty for their use. A 1N5820, 1N5821 or 1N5822 should be more than sufficient for these needs and would only cost a .2 volt drop. I've used them in voltage regulation applications with an LM-315T voltage regulator where my source voltage was 12 volts and I was trying to get 9 volts out. A .7 volt drop is significant in this application and that's why I reached for the Schottky diode.

REPLY







Dec 3, 2009. 8:52 AMRick_Covert says:

Sorry I meant to say that I used an LM-317T voltage regulator.

REPLY







Nov 22, 2009. 9:37 AMemerson.john says:

Do not put a diode in it. It will only cause the voltage available from that tiny solar array to drop .7V, and will thus degrade charging performance. Try to rember not to connect anything backwards and there is no reason for the diode. There is certainly no way it can IMPROVE performance.

REPLY







Jan 11, 2009. 11:16 AMkpdyer says:

hey, i did this but modified it a bit. The power is going through but the phone (an old Nokia 2610) won't charge, no matter how long I leave it up. what is happening???

REPLY







Oct 16, 2009. 12:24 AMsharlston says:

a diode is he answer

REPLY







Oct 16, 2009. 12:24 AMsharlston says:

hey i would insert a diode in there

REPLY







Oct 1, 2009. 10:58 AMColonel88 says:

Some phones will not charge because they are "stupid" Like u cannot just hookip a 5 volt regulator (7805) to a 9 volt battery and charge the itouch. It doesnt work and oh please put a diode on this or the charger will suck badly. :DD

REPLY







Aug 16, 2009. 7:16 PMsoapsayhello says:

I am in China. Please email me soapsayhello@hotmail for solar cell phone chargers.

REPLY







Jun 28, 2009. 6:36 AMreno91 says:

where do i get tha stuff

REPLY







Apr 15, 2009. 6:35 AM11avumkh says:

hey people out there i need a lil help with a something something im in Cape Town, South African and i need to find out where to buy the materials for a solar powered phone charger Do answer Shot ; - )

REPLY







Feb 6, 2009. 11:01 PMimakethings says:

did u add a diode?

REPLY







Jan 27, 2009. 1:36 AMbeayayan says:

hey guys... i need your help i have a thesis proposal regarding in this topic "solar charger. email me at greencol07@yahoo.com if you have any suggestion. thanks it will be big previleges to me

REPLY







Oct 8, 2008. 8:27 PMgentlehorse says:

Hi, your cell phone charger is cool. Is there anything to prevent the phone from overcharging? Thanks, Doug

REPLY







Nov 6, 2008. 4:25 PMBriguy9 says:

you might have an old junky phone. Most new ones have sensors that sense when the battery is full and stops taking electricity from the power source, even though its still plugged in.

REPLY







Oct 29, 2008. 2:33 PMkpdyer says:

hey i'm doing a science fair project involving solar charging a cell phone and i saw this... would you mind if i based it on this instuctable and others like it? Also, about how much would it cost, and do you recommend any other instructables?

REPLY







Oct 11, 2008. 1:47 PMNoname23 says:

Deliverance, nice. XD

REPLY







Sep 1, 2008. 5:20 PMgiloray says:

woah........this is so cool..but how much is the total cost of the equipments that are used is making the device?... can anyone there help me in finding some research/....

REPLY







Aug 15, 2008. 9:07 PMguitarmansmitty says:

Sorry but I need to ask if anyone has actually done this one yet. The reason I ask is that I don't want to fry my battery and have to get another one (if I can even find one).

REPLY







Aug 14, 2008. 12:26 PMHeavy Metal Handyman says:

Dude I built the thing and had to make about 50 of em and let me tell you that solar cells VARY ALOT. Not one of the 100 solar cells was exact as per the specks (I painfully checked each one with my meter a very slow process indeed). I would suggest in purchasing 4 or 5 solar cells and take the highest voltage of the bunch and pair them together, thats what I did. I had no problem with the voltage being too high because of the low amperage. 7 and 8 volts was optimum for charging a dead cell phone. The ones I build for this demonstration worked but the sun must be bright. Again some worked better do to the large variation in solar cells strength. Lesson learned, ALL SOLAR CELLS ARE NOT CREATED EQAUL. No voltage regulator is required as far as the ones I built. Keep in mind the price you pay for something, 2 solar cells = 16.50 altoids tin 1.50 = $18.00 thats not including all the tape and solder and heatsrink tubing .....when you can already buy on the market wink wink for say $19.00.



REPLY







Aug 12, 2008. 9:15 AMalex-sharetskiy says:

put solar panels on both sides of the altoids tin, (on the inside) you might also want to add a voltage regulator so you don't kill your phone

REPLY







Aug 14, 2008. 9:11 AMNirjuana says:

Probably regulator wouldn't work because they usually need about +2 volts larger input voltage than the output voltage. Simple voltage divider would work but it decreases efficiency. And I'm not even sure can you charge your phone with 30 mAh current...

REPLY







Aug 14, 2008. 9:12 AMNirjuana says:

Sorry, I meant 20 mAh current.

REPLY







Aug 14, 2008. 9:43 AMalex-sharetskiy says:

the voltage regulators that i have, they would work, if you put 4 volts through them, you would get 3.5+/- volts out using a 5v regulator you probably could charge your phone, but the power you put into it, would be eaten by the phone's "check for signal" thing, so you might have to turn your phone off in order to charge it

REPLY







Aug 14, 2008. 10:36 AMNirjuana says:

At least my charger gives out 5 volt so I'm no sure could it be run with anything below it. But I recommend to get some better solar cells, for example, you can get solar cells from DealExtreme that give out 80mAh @ 4V for 8.25$. And they're not even so big, 2.36 in x 2.36 in so it could be used for many purposes.

REPLY







Aug 11, 2008. 6:23 PMjillg says:

this is cool I've always liked solar powered gadgets oh also... First (always wanted to say that!)

REPLY



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Saturday, January 23, 2010

bug

FM Telephone Bug
Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to build and is therefore a good, useful beginner project.
Schematic

This is the schematic of the phone transmitter
Parts

Part

Total Qty.

Description

Substitutions
R1 1 180 Ohm 1/4 W Resistor
R2 1 12K 1/4 W Resistor
C1 1 330pF Capacitor
C2 1 12pF Capacitor
C3 1 471pF Capacitor
C4 1 22pF Capacitor
Q1 1 2SA933 Transistor
D1, D2, D3, D4 4 1SS119 Silicon Diode
D5 1 Red LED
S1 1 SPDT Switch
L1 1 Tuning Coil
MISC 1 Wire, Circuit Board

Notes
1. L1 is 7 turns of 22 AWG wire wound on a 9/64 drill bit. You may need to experiment with the number of turns.
2. By stretching and compressing the coils of L1, you can change the frequency of the transmitter. The min frequency is about 88 Mhz, while the max frequency is around 94 Mhz.
3. The green wire from the phone line goes to IN1. The red wire from the phone line goes to IN2. The green wire from OUT1 goes to the phone(s), as well as the red wire from OUT2.
4. The antenna is a piece of thin (22 AWG) wire about 5 inches long.
5. All capacitors are rated for 250V or greater.
6. The transmitter is powered by the phone line and is on only when the phone is in use. S1 can be used to turn the transmitter off if it is not needed.
7. If you have problems with the LED burning out, then add a 300 ohm 1/4W resistor in series with it.
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3 Watt FM Transmitter

3 Watt FM Transmitter

By Rae XL Tkacik
This is the schematic for an FM transmitter with 3 to 3.5 W output power that can be used between 90 and 110 MHz. Although the stability isn't so bad, a PLL can be used on this circuit.
This is a circuit that I've build a few years ago for a friend, who used it in combination with the BLY88 amplifier to obtain 20 W output power. From the notes that I made at the original schematic, it worked fine with a SWR of 1 : 1.05 (quite normal at my place with my antenna).

Schematic
This is the schematic of the 3W FM Transmitter
Parts:

Part

Total Qty.

Description

Substitutions
R1,R4,R14,R15 4 10K 1/4W Resistor
R2,R3 2 22K 1/4W Resistor
R5,R13 2 3.9K 1/4W Resistor
R6,R11 2 680 Ohm 1/4W Resistor
R7 1 150 Ohm 1/4W Resistor
R8,R12 2 100 Ohm 1/4W Resistor
R9 1 68 Ohm 1/4W Resistor
R10 1 6.8K 1/4W Resistor
C1 1 4.7pF Ceramic Disc Capacitor
C2,C3,C4,C5,C7,C11,C12 7 100nF Ceramic Disc Capacitor
C6,C9,C10 3 10nF Ceramic Disc Capacitor
C8,C14 2 60pF Trimmer Capacitor
C13 1 82pF Ceramic Disc Capacitor
C15 1 27pF Ceramic Disc Capacitor
C16 1 22pF Ceramic Disc Capacitor
C17 1 10uF 25V Electrolytic Capacitor
C18 1 33pF Ceramic Disc Capacitor
C19 1 18pF Ceramic Disc Capacitor
C20 1 12pF Ceramic Disc Capacitor
C21,C22,C23,C24 4 40pF Trimmer Capacitor
C25 1 5pF Ceramic Disc Capacitor
L1 1 5 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L2,L3,L5,L7,L9 5 6-hole Ferroxcube Wide band HF Choke (5 WDG)
L4,L6,L8 3 1.5 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L10 1 8 WDG, Dia 5 mm, 1 mm CuAg, Space 1 mm
D1 1 BB405 BB102 or equal (most varicaps with C = 2-20 pF [approx.] will do)
Q1 1 2N3866
Q2,Q4 2 2N2219A
Q3 1 BF115
Q5 1 2N3553
U1 1 7810 Regulator
MIC 1 Electret Microphone
MISC 1 PC Board, Wire For Antenna, Heatsinks

Notes:
1. Email Rae XL Tkacik with questions, comments, etc.
2. The circuit has been tested on a normal RF-testing breadboard (with one side copper). Make some connections between the two sides. Build the transmitter in a RF-proof casing, use good connectors and cable, make a shielding between the different stages, and be aware of all the other RF rules of building.
3. Q1 and Q5 should be cooled with a heat sink. The case-pin of Q4 should be grounded.
4. C24 is for the frequency adjustment. The other trimmers must be adjusted to maximum output power with minimum SWR and input current.
5. Local laws in some states, provinces or countries may prohibit the operation of this transmitter. Check with the local authorities.
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Schematic This is the schematic of the 3W FM Transmitter