I was looking through an electronics catalog today and noticed the section on Voltage Regulators. What I would like to know is why is everyone using inefficient resistors that just burn battery power with nothing being accomplished? I've never used a Voltage Regulator chip personally (yet), but from what I've been reading about them, it seems like the perfect solution to handling LED voltage issues. According to the chip that I was looking at earlier today, this Voltage Regulator chip only burns 1.2ua. Yes that's micro-amps, not milli-amps, and it is rated to handle up to 16 volts, so why isn't everyone using them instead of resistors? It can't be the price because all of these chips that I looked at today cost less than $1.00 in the Mouser electronics catalogue. They have chips rated at 3.5v and 4.0v so it would seem that they would be perfect for LED flashlight conversions. That way, there would be no need for a dummy battery (to go from 4 cells to 3) or a resistor that does nothing but waste battery power. Also, if these chips keep a constant voltage, then you should be able to get a consistent brightness till the batteries finally crap out. I don't know guys, what am I missing? There must be some reason that everyone isn't using these things in place of wasteful resistors. What is the downside? Would someone that is familiar with these chips please enlighten us on the subject? As always, thanks in advance for any and all info.
Voltage Regulators
- Thread starter X-CalBR8
- Start date
Help Support Candle Power Flashlight Forum
D
**DONOTDELETE**
Guest
Sorry, sorry, sorry, to pop out your dreams...
The kind of IC you are talking about are so called "linear regulators", which act like a variable resistor burning exactly as much voltage to keep the output voltage constant. There is power dissipated to heat like in a resistor. You can calculate it: (Input voltage - Output voltage) x current = power burnt in the regulator.
The supply current of some yA is just what the IC itself needs.
You can divide in some categories:
- positive vs. negative regulators, which work in the + vs. - lead (78XX pos., 79XX neg.)
- fixed output voltage regs ( 7X05 = 5 V fixed, 7X12 = 12V fixed, etc.) vs. adjustable regulators, where you can adjust the voltage by two resistors (f.e. LM317)
- Standard vs. "Low Drop"-types (LD): Standard regulators need an input voltage at least 3 V above output voltage, the LD types can handle down to 0.5V input-output difference.
Take a standard fixed 5 V positive regulator: The 7805.
It has three pins, which are (read on the front, from left to right): 1 Input, 2 Ground, 3 Output.
Input and output ground is the same, so connect them together and connect the middle pin to it also. Now connect input + to the left pin, and ouput + to the right pin.
You will need four additional caps to ensure proper operation preventing the VR to oscillate: Put an electrolyte cap and a small ceramic cap parallel between input and ground and also between output and ground not more than 1 inch away from the IC.
Ok, this will give you a regulated 5V from an 8 to 36(?) V input source.
Now it comes to cooling. Calculate the power generated in the IC by the formula above. Example: You have a 18V source and want to draw 500 mA from the 5V. 13V x 0.5A = 6.5 Watts! That is a lot of power, which will make your IC extremly hot in a few seconds. So you need a cooling body. You know the black aluminium pieces with the strange shape? Choose one (better larger than too small) and mount the IC (insulated!) on the cooling body, having good thermal contact.
Ok, then check it out.
There is a lot more to say about different VRs, there are more sophisticated on the marked, but this deals with the "Over 1 billion sold"-types.
If you want to know more, please tell me.
Bye!
The kind of IC you are talking about are so called "linear regulators", which act like a variable resistor burning exactly as much voltage to keep the output voltage constant. There is power dissipated to heat like in a resistor. You can calculate it: (Input voltage - Output voltage) x current = power burnt in the regulator.
The supply current of some yA is just what the IC itself needs.
You can divide in some categories:
- positive vs. negative regulators, which work in the + vs. - lead (78XX pos., 79XX neg.)
- fixed output voltage regs ( 7X05 = 5 V fixed, 7X12 = 12V fixed, etc.) vs. adjustable regulators, where you can adjust the voltage by two resistors (f.e. LM317)
- Standard vs. "Low Drop"-types (LD): Standard regulators need an input voltage at least 3 V above output voltage, the LD types can handle down to 0.5V input-output difference.
Take a standard fixed 5 V positive regulator: The 7805.
It has three pins, which are (read on the front, from left to right): 1 Input, 2 Ground, 3 Output.
Input and output ground is the same, so connect them together and connect the middle pin to it also. Now connect input + to the left pin, and ouput + to the right pin.
You will need four additional caps to ensure proper operation preventing the VR to oscillate: Put an electrolyte cap and a small ceramic cap parallel between input and ground and also between output and ground not more than 1 inch away from the IC.
Ok, this will give you a regulated 5V from an 8 to 36(?) V input source.
Now it comes to cooling. Calculate the power generated in the IC by the formula above. Example: You have a 18V source and want to draw 500 mA from the 5V. 13V x 0.5A = 6.5 Watts! That is a lot of power, which will make your IC extremly hot in a few seconds. So you need a cooling body. You know the black aluminium pieces with the strange shape? Choose one (better larger than too small) and mount the IC (insulated!) on the cooling body, having good thermal contact.
Ok, then check it out.
There is a lot more to say about different VRs, there are more sophisticated on the marked, but this deals with the "Over 1 billion sold"-types.
If you want to know more, please tell me.
Bye!
Go Go Gadget Flashlight
Enlightened
From a simplicity standpoint, resistors are the way to go. Cheap and easy to understand.
The only way (that I know of) to get a low-loss voltage regulation is to use pulse-width-modulation, PWM.
Instead of sapping some of the power away to regulate voltage, it turns it on and off very fast. This way, your load sees a higher voltage than it really wants, but only for a very brief moment.
Phantomas, any comments?
The only way (that I know of) to get a low-loss voltage regulation is to use pulse-width-modulation, PWM.
Instead of sapping some of the power away to regulate voltage, it turns it on and off very fast. This way, your load sees a higher voltage than it really wants, but only for a very brief moment.
Phantomas, any comments?
Phantomas2002: Thanks for the info. I can always depend on you for a great technical explanation of things. I learned a lot from your explanation and thank you for taking the time to explain it to us. I never knew that Voltage Regulators worked by means of variable resistance. I'm curious though about what happens when the voltage level drops below the voltage level that the voltage regulator is set to. Say, for instance, that you have a 4volt voltage regulator that is running on 6volts and the batteries run down to the point of dropping below 4volts, what happens then? Does it offer zero resistance and act as though it's not even there or does the whole circuit cease to function.
Hi Phantomas, I was wondering about the pulsing concept but I not sure I really understand it. When used as a regulator does it increase the rate and duration of each pulse as the voltage drops down...and at some point simply stop pulsing and stay on all the time at which point the light slowly fades linearly as the power continues to drop?
If so would you happen to know it this is how the I/C works in the Lightwave product line?
Thanks
Ken
If so would you happen to know it this is how the I/C works in the Lightwave product line?
Thanks
Ken
D
**DONOTDELETE**
Guest
Phontomas2002:
You seem very knowledgeable about the miriad of power supply chips available- what do you think is the most suitable for a step-up type to drive LEDs in flashlight applications? Of consideration would be:
1. ease of use (can the package be soldered to a board without special tools or skills)
2. needing a minumum of extra components (has most built into its package)
3. Cost and availability
4. Efficiency
5. Adjustability (can be adjusted for maximum LED output or lowered for long life
I think a step up type is most desireable (as opposed to the buck type) because it offers the possibility of using smaller number of cells; thus a smaller total package. I think most buck type would need at least 6V or 4 regular alkalines to work at 3.6 V. Of course, using more cells would still be possible if one wanted greater capacity.
What do you think?
Chet
You seem very knowledgeable about the miriad of power supply chips available- what do you think is the most suitable for a step-up type to drive LEDs in flashlight applications? Of consideration would be:
1. ease of use (can the package be soldered to a board without special tools or skills)
2. needing a minumum of extra components (has most built into its package)
3. Cost and availability
4. Efficiency
5. Adjustability (can be adjusted for maximum LED output or lowered for long life
I think a step up type is most desireable (as opposed to the buck type) because it offers the possibility of using smaller number of cells; thus a smaller total package. I think most buck type would need at least 6V or 4 regular alkalines to work at 3.6 V. Of course, using more cells would still be possible if one wanted greater capacity.
What do you think?
Chet
D
**DONOTDELETE**
Guest
How soon we forget?
what about the LM334Z, it's the only way to go and it's all I use when I make my flashlights.
what about the LM334Z, it's the only way to go and it's all I use when I make my flashlights.
D
**DONOTDELETE**
Guest
LM334 10mA current source would not be enough to drive an LS.
...unless I put 35 of them in parallel.
Are there IC current sources that give out 350 mA from 4-6V source input?
...unless I put 35 of them in parallel.
Are there IC current sources that give out 350 mA from 4-6V source input?
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Eater of Ghosts:
How soon we forget?
what about the LM334Z, it's the only way to go and it's all I use when I make my flashlights.
<HR></BLOCKQUOTE>
----------------------------------------
Hmmmm...it seems like it slipped through my cracks anyway.
Is that 1.6 ohms?
How soon we forget?
what about the LM334Z, it's the only way to go and it's all I use when I make my flashlights.
----------------------------------------
Hmmmm...it seems like it slipped through my cracks anyway.
Is that 1.6 ohms?
Silviron
Flashlight Enthusiast
Hi Gang-
I've been "lurking" for a couple of weeks now and have really enjoyed everyone's posts and enthusiasm for LED lights. I'm pretty much a beginner at this, even though I did make my first LED flashlight back in 1974!
Anyway, you may all know about these neat design tools, but I don't recall seeing them posted here... They are quite appropriate to this particular thread:
National Semiconductor has (free) an online tool that will allow you to design and build a power supply "online" at:
http://www.national.com/appinfo/power/webench/buildit/index.html
And a free downloadable (10 MB file) program which will allow you to design a DC-DC step-up converter (switcher) on your own computer.. That is at:
http://www.national.com/appinfo/power/0,1768,383,00.html
If this is old hat to everyone, I apoligize - If it is new to you, I think that you may find it very useful. I havn't actually BUILT anything from the plans yet, but have tried several designs- Gotta get the parts all ordered and figure out which to build first.
I've been "lurking" for a couple of weeks now and have really enjoyed everyone's posts and enthusiasm for LED lights. I'm pretty much a beginner at this, even though I did make my first LED flashlight back in 1974!
Anyway, you may all know about these neat design tools, but I don't recall seeing them posted here... They are quite appropriate to this particular thread:
National Semiconductor has (free) an online tool that will allow you to design and build a power supply "online" at:
http://www.national.com/appinfo/power/webench/buildit/index.html
And a free downloadable (10 MB file) program which will allow you to design a DC-DC step-up converter (switcher) on your own computer.. That is at:
http://www.national.com/appinfo/power/0,1768,383,00.html
If this is old hat to everyone, I apoligize - If it is new to you, I think that you may find it very useful. I havn't actually BUILT anything from the plans yet, but have tried several designs- Gotta get the parts all ordered and figure out which to build first.
D
**DONOTDELETE**
Guest
Hi Guys!
I havent been online for some days (went mountainclimbing) and I am surprised about the number of posts and the questions belonging to voltage regulators and the question itself, how to deliver power to LEDs.
I like building little smart power supplies and optimizing them (also minimizeng them, "reduce to the max"), so I got a little knowledge meanwhile, and I will be happily sharing it.
1. In my opinion the best to supply LEDs is to use one, two or three cells, more are getting bulky and heavy. In all three cases the voltage is below, or can drop below 4 V, the voltage required to drive the LEDs. So my designs have a sep up circuit. There is a little problem when you use 3 cells. Then initially the voltage is ABOVE 4 V, later BELOW 4V. This would make a need for a Step-up/step-down converter, which is more difficult to build (so called flyback-converter, needs a special coil). I just use always 2 or more LEDs in a row, so the battery voltage is ALWAYS under the required voltage, making good conditions for a stepup.
2. There are two different principles of stepup converters: capacitor charge pumps and coil driven ones.
The charge pumps use cheaper, easier to find parts, but are usable only for smaller power amounts (up to 100 or 200 mA), also you can only DOUBLE a voltage (so for stepping up 1 cell you would need 2 converters in a row...).
The coil driven ones are my choice, they are for higher power (e.g. driving 36 LEDs in a 3Dcell MagLite), and better adjustable, also they can make high voltage ratings (e.g. 15V out of 3 V).
3. There are a LOT of Coil driven stepups out there on the market, because of the boom of handheld devices (cellular phones, PDAs, Discmans, MP3 players, etc.).
Known companies with good products are: Linear Technology, MAXIM, and National Semiconductor, as well as many others. I prefer Linear, because they always send me free samples of the ICs.
The disadvantage of these ICs is that they are usually only available in SMD packages (Surface Mounted Devices), which means they are tiny and REALLY small, but are also difficult to solder, but with a quiet hand and a good eye and some experience, you dont need any special equipment.
A good IC which requires few external components is the LT1308, which drives my 36LED Mag.
If you have some problems getting the coils (most electronic shops dont have the right coils), just give the manufacturer (coiltronics, etc.) a call and get some samples. In the datasheets of Linear Technologies are always the part numbers for the coils, so it will be easy.
When I make SMD boards, and want to make only one or two, I dont start the chemical itching machine. I just take a fine drilling tool (like the DREMEL) with a 0.5 mm tip and work out the spaces between the lines. This is fast and good.
Any comments and/or questions welcome
Ok, now back to the regulator thing:
1. When the input voltage of a regulator slowly drops, getting under the 3 V above output, it will start oscillating in a strange way (I had odd errors with that...), when the voltage drops further, it will behave as it would not be there...
2. PWM: (pulse width modulation)
A fine concept, to reduce the power delivered to an output without burning voltage like a linear regulator.
An example:
You want to drive a resistor of 1 Ohm with 4 Volts from a source of 8 Volts.
So instead of reducing the voltage by burning 4 Volts, you can switch on and off the resistor.
But: If you think, you will switch on for 50% of the time and then switch off for 50% of the time, this would make a middle of 50% x 8V = 4V, you are WRONG!!
Calculating this, you will have to look at the POWER, not the Voltage!
Power needed:
P = U x I ( Power = voltage x current )
You dont have the current, but can be calculated also:
I = U / R (current = voltage / resistance )
so P = U x U / R ( formula 1 in formula 2)
P = 4V x 4V / 1Ohm = 16 Watts
Ok, but when you hook the 1 Ohm resistor to 8 Volts, you get:
P = 8V x 8V / 1Ohm = 64 Watts !!!
So when you have 50% on time and 50% off time, you will deliver 64 x 50% = 32 Watts to the resistor, not the desired 16 watts.
So the right On-time will calcualte at 16W / 64W = 25%
Ok, why do all this?
The PWM works fine for resistors, and is often used for Lamps (indescendent !!), etc.
But when you use more complex loads like LEDs, it is getting complicated. A LED doesnt pull the double current when given double voltage, so you will not be able to calculate the on/off percentages.
Also when you drive a LED at high current (also when only for a few microseconds), the efficiency drops.
You can use a capacitor or a coil between the PWM regulator and the LED to smooth the voltage and current. But this is far too complex to calculate. You can build and try and adjust with a potentiometer.
All in all it is a lot of work, and I prefer an easy to use, high integrated circuit.
By the way: A step down converter (buck) is nothing else than a PWM plus a coil...
Ok, guys, so much for now, it makes fun to discuss with you ! If anybody wants to build a stepup/down/? for a specific purpose, feel free to tell me, I will assist as good as I can.
Bye!
I havent been online for some days (went mountainclimbing) and I am surprised about the number of posts and the questions belonging to voltage regulators and the question itself, how to deliver power to LEDs.
I like building little smart power supplies and optimizing them (also minimizeng them, "reduce to the max"), so I got a little knowledge meanwhile, and I will be happily sharing it.
1. In my opinion the best to supply LEDs is to use one, two or three cells, more are getting bulky and heavy. In all three cases the voltage is below, or can drop below 4 V, the voltage required to drive the LEDs. So my designs have a sep up circuit. There is a little problem when you use 3 cells. Then initially the voltage is ABOVE 4 V, later BELOW 4V. This would make a need for a Step-up/step-down converter, which is more difficult to build (so called flyback-converter, needs a special coil). I just use always 2 or more LEDs in a row, so the battery voltage is ALWAYS under the required voltage, making good conditions for a stepup.
2. There are two different principles of stepup converters: capacitor charge pumps and coil driven ones.
The charge pumps use cheaper, easier to find parts, but are usable only for smaller power amounts (up to 100 or 200 mA), also you can only DOUBLE a voltage (so for stepping up 1 cell you would need 2 converters in a row...).
The coil driven ones are my choice, they are for higher power (e.g. driving 36 LEDs in a 3Dcell MagLite), and better adjustable, also they can make high voltage ratings (e.g. 15V out of 3 V).
3. There are a LOT of Coil driven stepups out there on the market, because of the boom of handheld devices (cellular phones, PDAs, Discmans, MP3 players, etc.).
Known companies with good products are: Linear Technology, MAXIM, and National Semiconductor, as well as many others. I prefer Linear, because they always send me free samples of the ICs.
The disadvantage of these ICs is that they are usually only available in SMD packages (Surface Mounted Devices), which means they are tiny and REALLY small, but are also difficult to solder, but with a quiet hand and a good eye and some experience, you dont need any special equipment.
A good IC which requires few external components is the LT1308, which drives my 36LED Mag.
If you have some problems getting the coils (most electronic shops dont have the right coils), just give the manufacturer (coiltronics, etc.) a call and get some samples. In the datasheets of Linear Technologies are always the part numbers for the coils, so it will be easy.
When I make SMD boards, and want to make only one or two, I dont start the chemical itching machine. I just take a fine drilling tool (like the DREMEL) with a 0.5 mm tip and work out the spaces between the lines. This is fast and good.
Any comments and/or questions welcome
Ok, now back to the regulator thing:
1. When the input voltage of a regulator slowly drops, getting under the 3 V above output, it will start oscillating in a strange way (I had odd errors with that...), when the voltage drops further, it will behave as it would not be there...
2. PWM: (pulse width modulation)
A fine concept, to reduce the power delivered to an output without burning voltage like a linear regulator.
An example:
You want to drive a resistor of 1 Ohm with 4 Volts from a source of 8 Volts.
So instead of reducing the voltage by burning 4 Volts, you can switch on and off the resistor.
But: If you think, you will switch on for 50% of the time and then switch off for 50% of the time, this would make a middle of 50% x 8V = 4V, you are WRONG!!
Calculating this, you will have to look at the POWER, not the Voltage!
Power needed:
P = U x I ( Power = voltage x current )
You dont have the current, but can be calculated also:
I = U / R (current = voltage / resistance )
so P = U x U / R ( formula 1 in formula 2)
P = 4V x 4V / 1Ohm = 16 Watts
Ok, but when you hook the 1 Ohm resistor to 8 Volts, you get:
P = 8V x 8V / 1Ohm = 64 Watts !!!
So when you have 50% on time and 50% off time, you will deliver 64 x 50% = 32 Watts to the resistor, not the desired 16 watts.
So the right On-time will calcualte at 16W / 64W = 25%
Ok, why do all this?
The PWM works fine for resistors, and is often used for Lamps (indescendent !!), etc.
But when you use more complex loads like LEDs, it is getting complicated. A LED doesnt pull the double current when given double voltage, so you will not be able to calculate the on/off percentages.
Also when you drive a LED at high current (also when only for a few microseconds), the efficiency drops.
You can use a capacitor or a coil between the PWM regulator and the LED to smooth the voltage and current. But this is far too complex to calculate. You can build and try and adjust with a potentiometer.
All in all it is a lot of work, and I prefer an easy to use, high integrated circuit.
By the way: A step down converter (buck) is nothing else than a PWM plus a coil...
Ok, guys, so much for now, it makes fun to discuss with you ! If anybody wants to build a stepup/down/? for a specific purpose, feel free to tell me, I will assist as good as I can.
Bye!
Phantomas2002: I just want to say a big thank you for all the great info! That answered a lot of questions that I was wondering about. You mentioned that if we had a specific purpose that it would be OK to ask about it and I have a mod that I would like to do on a 4 AA Energizer DoubleBarrel. As you probably already know, it is series/parallel and comes to 3volts. What I would like to know is can you please draw us a schematic for using the LT1308 chip that you mentioned earlier that would be powerful enough to run a 18 or 24 LED array at the 3volt input? Also this page mentions that there is a newer version of the LT1308 chip. http://www.arrow.com/www_engineers/arrow_analog/products/lt1308.html Is it worth trying to get the newer version or are they about the same? I tried to find the LT1308 in the latest Mouser Electronics catalog as I'm about to place an order with them soon anyway, but I couldn't find it there. Any suggestions on where to find this elusive chip in the U.S.? Thank you very much for any and all help. I'm having a lot of fun learning about this and working on this mod and your help is much appreciated.
Hey, I just happened to think of something else. This voltage range would also be perfect for the 2.5volt super cap project that I'm working on. The info on the chip says it's supposed to be good down to 1volt which should give a wide operating voltage range. 1-2.5volts. This would be wonderful if I could use the same circuit on both projects. This is getting better and better.
D
**DONOTDELETE**
Guest
Thanks Phantomas2002 for your lengthy and highly informative post. You'll probably regret making your generous offer of assistance as you will surely be put to the test! However, there are a lot of needy people out here that are trying to make the big step up from stone-age resistor circuits to sophisticated ICs and we all need some help.
Chet
Chet
I agree with Chet and the rest. Thank you Phantomas2002
You also speak ( unintentionally I am sure ) partially over my head. I know Ohms law ,etc but the IC stuff fries me. I downloaded the circuit designer Silverion suggested. It was pretty cool, I designed a circuit, but I have no idea what I have done...LOL I am not sure if I am powering a space shuttle or LED. I would really like to buy a kit someone could offer with the bare bone parts. I would not mind throwing in 10 bucks for the trouble and 3 bucks for postage + parts of course. Maxim has the prototype and I was going to buy that except Grnadsee came out with the new flashlight and I am going to spend 80 bucks on that rather than 100 on the proto.
So..
Thanks again for help
You also speak ( unintentionally I am sure ) partially over my head. I know Ohms law ,etc but the IC stuff fries me. I downloaded the circuit designer Silverion suggested. It was pretty cool, I designed a circuit, but I have no idea what I have done...LOL I am not sure if I am powering a space shuttle or LED. I would really like to buy a kit someone could offer with the bare bone parts. I would not mind throwing in 10 bucks for the trouble and 3 bucks for postage + parts of course. Maxim has the prototype and I was going to buy that except Grnadsee came out with the new flashlight and I am going to spend 80 bucks on that rather than 100 on the proto.
So..
Thanks again for help
D
**DONOTDELETE**
Guest
Hi Guys!
I am currently drawing a circuit using the LT1308B for you (the LT1308 is no longer produced, my designs use the LT1308B, but for constant load applications, you can use A or B type, it doesnt matter...).
There is a VERY good datasheet from Linear (20 pages!) about this IC. It shows how to make the board layout which is important when switching at 600 kHz. Also it tells manufacturer and order number of usable caps and coils. These two components are critical: As there is a very high switching frequency, the caps have to be good ones with low ESR (equivalent serial resitance). You can only take tantalum types here, and there are also big quality differences among them. The coil shoul have a low DC resistance as well as being able to stand the high startup currents of about 3 Amps without loosing too much inductivity.
Just have a look at the VERY good data sheet:
http://www.linear.com/pdf/1308a_bf.pdf
I will design all the resistor values, etc for you and you can then take the layout provided with the data sheet. The components are only available from the manufacturers. Just tell then you are an electric engineer, work for company XXXX, blah blah, and tell them you would PLEASE (!) like two samples. The people from Linear in Germany are VERY kind and helped me a lot!
To be continued... ...soon...
Bye!
I am currently drawing a circuit using the LT1308B for you (the LT1308 is no longer produced, my designs use the LT1308B, but for constant load applications, you can use A or B type, it doesnt matter...).
There is a VERY good datasheet from Linear (20 pages!) about this IC. It shows how to make the board layout which is important when switching at 600 kHz. Also it tells manufacturer and order number of usable caps and coils. These two components are critical: As there is a very high switching frequency, the caps have to be good ones with low ESR (equivalent serial resitance). You can only take tantalum types here, and there are also big quality differences among them. The coil shoul have a low DC resistance as well as being able to stand the high startup currents of about 3 Amps without loosing too much inductivity.
Just have a look at the VERY good data sheet:
http://www.linear.com/pdf/1308a_bf.pdf
I will design all the resistor values, etc for you and you can then take the layout provided with the data sheet. The components are only available from the manufacturers. Just tell then you are an electric engineer, work for company XXXX, blah blah, and tell them you would PLEASE (!) like two samples. The people from Linear in Germany are VERY kind and helped me a lot!
To be continued... ...soon...
Bye!
Phantomas2002: I just wanted to be the first to thank you for your very kind offer to help us out with a schematic. This will be my first project using SMDs so any and all tips will be much appreciated. Are there any special tools necessary to work with SMDs or do you just need a soldering iron? Also how hot can you get SMDs when soldering? Should I use the 15watt or 30watt setting on my soldering iron? I'm very excited about this project and can hardly wait to see the schematic you are working on for us. I was just thinking that it would also make for a cool project to use this circuit on a 2D Mag-Lite to. My imagination is soaring with new possibilities.
D
**DONOTDELETE**
Guest
Ok, a few words to these itzy-bitzy-small SMD parts
:
For soldering SMD, 5W is enough, so use the 15W setting. A regulated (keeps the temerature, not the power constant) soldering iron is good, but not necessary.
What is important and makes things much easier is a FINE tip! If you dont have one, you can make one yourself by filing one to a fine needle of approx. 30 degrees. The tip should be made of copper, which is soft enough to be worked on easily. Then use tin to make the tip perfect.
If you dont want to start with the stepup parts you just bought, go to radioshack or whateveer and buy some SMD parts, resistors, transistors, caps, etc. (the cheap ones) and a SMD experimental board where tabs for soldering SMDs are already per-itched. (This compares to the many-holes PCBs for regular electronic parts). Try soldering with the cheap parts. If you spen an hour or so, you will be a perfect SMD-solderer
.
For the technique itself: You can use different methods. IMHO the easiest is to glue the part with cyanacrylate (only a LITTLE drop!!!) in place and then solder with thin SMD solder (0.5mm diameter). Or you can buy some solder paste (small tin pieces with flowing agent) and put it onto the tabs, setting the part on and solder with a hot air gun.
Just try a little and find out what you like!
If your soldering iron is way too big, consider buying a SMD iron. I bought a 5W SMD iron for under 5$ and it works well.
I will post the circuit a.s.a.p. !
Bye!
For soldering SMD, 5W is enough, so use the 15W setting. A regulated (keeps the temerature, not the power constant) soldering iron is good, but not necessary.
What is important and makes things much easier is a FINE tip! If you dont have one, you can make one yourself by filing one to a fine needle of approx. 30 degrees. The tip should be made of copper, which is soft enough to be worked on easily. Then use tin to make the tip perfect.
If you dont want to start with the stepup parts you just bought, go to radioshack or whateveer and buy some SMD parts, resistors, transistors, caps, etc. (the cheap ones) and a SMD experimental board where tabs for soldering SMDs are already per-itched. (This compares to the many-holes PCBs for regular electronic parts). Try soldering with the cheap parts. If you spen an hour or so, you will be a perfect SMD-solderer
For the technique itself: You can use different methods. IMHO the easiest is to glue the part with cyanacrylate (only a LITTLE drop!!!) in place and then solder with thin SMD solder (0.5mm diameter). Or you can buy some solder paste (small tin pieces with flowing agent) and put it onto the tabs, setting the part on and solder with a hot air gun.
Just try a little and find out what you like!
If your soldering iron is way too big, consider buying a SMD iron. I bought a 5W SMD iron for under 5$ and it works well.
I will post the circuit a.s.a.p. !
Bye!
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Phantomas2002:
Ok, a few words to these itzy-bitzy-small SMD parts
:
IMHO the easiest is to glue the part with cyanacrylate (only a LITTLE drop!!!) in place and then solder with thin SMD solder (0.5mm diameter).
Bye!<HR></BLOCKQUOTE>
Brilliant!!!!!
I squeezed a dab of glue on an index card, used a needle to place just enough where I wanted it. It worked perfectly!!!!! I had pretty much given up on SMD but I will give it a try again now.
Keep these tips coming!!!!
Ok, a few words to these itzy-bitzy-small SMD parts
IMHO the easiest is to glue the part with cyanacrylate (only a LITTLE drop!!!) in place and then solder with thin SMD solder (0.5mm diameter).
Bye!<HR></BLOCKQUOTE>
Brilliant!!!!!
I squeezed a dab of glue on an index card, used a needle to place just enough where I wanted it. It worked perfectly!!!!! I had pretty much given up on SMD but I will give it a try again now.
Keep these tips coming!!!!
