hair straightener Soldering hotplate

[capwizard]

Re: hair straightener Soldering hotplate

Thank you Mr. diif

first things I did in the morning was to test this controversy PTC thermistor. Yes, First it shows 9.8 K ohms but when I squeeze it they change it to 534.6k and then after 10 minutes it changes back to 323.2K ohms

I think it’s very strange that when I am extruding this PTC which will change the resistance. So I opened one ptc to see what was happened and the result is two pieces of metal, they don't even touch each other? I think that's the reason why.

I have a question can we use this as a pressure sensor?

[diif]

Re: hair straightener Soldering hotplate

0.8 k ohms on the one I've used and tested and 1.5 k ohms on my other.

[gabiz_ro]

Re: hair straightener Soldering hotplate

Could be some NTC and PTC combined.
Don't remember mine if is 250 or 270 Celsius at 220V
But reading are
cold 3.58k
5 sec 0.7k increase quick
10 sec 218 ohm increase slowly
60 sec 244 ohms slowly decrease to 188 ohm then slowly increase to 260 ohms then fluctuate between 260-270 ohms and 0.35-0.4k few seconds later 0.6k and increasing (but during noted last sequence and check again was 0.45k and increasing)
To be more clear:
After disconnect
244 ohms and slowly decreasing until reach 188 ohms
Then slowly increased until 260 ohms
Then start to fluctuate
261 ohms 0.35 Kohms
264 ohms 0.38 Kohms
268 ohms 0.39 Kohms
270 ohms 0.4 Kohms
Then jump to 0.6 Kohms ind increasing slowly
Few seconds later when I check again was 0.45 Kohms and slowly increasing

[budm]

Re: hair straightener Soldering hotplate

Your result shows the resistance goes down with an increase of temperature that will make it NTC, something is not right. Are yuu sure your meter is OK? Resistance to be in 100's of thousands of Ohms at room temp does not sounds right.
May be Diff can verify the results of his PTC.
You can find out what the resistance is by measuring Current and V drops then calculate the resistance.


If you cool the ceramics the resistance will
decrease and more power/energy will pass.

https://www.gmnameplate.com/company/...re-ptc-heaters

PTC heaters utilize Positive Temperature Coefficient materials i.e. materials that exhibit a positive resistance change in response to the increase in temperature. As the temperature increases, the electrical resistance of the material also increases, thus limiting the current flow. Simply put, the material allows current to pass when it’s cold, and restricts current to flow as the threshold temperature increases.

[sam_sam_sam]

Re: hair straightener Soldering hotplate

but-but-but my friend I don't even know what is happening?

Yes yes yes

You have given the information about the way these device behaves and that is a lot of useful information

29.1c now, PTC is at 298.3k ohms I just barely touched it with my hand and it changed to 91.5k ohms @ 29.5 c then I connect it to the electricity for 3 seconds it goes down to 5.0 ohms. 29.1c now, PTC is at 298.3k ohms I just barely touched it with my hand and it changed to 91.5k ohms @ 29.5 c then I connect it to the electricity for 3 seconds it goes down to 5.0 ohms.

I have to agree with you that this is very strange behavior for a device

I have one question for you what is the resistance of the device after it gets to operating temperature

As I have mentioned before I have a plan for using a couple of these heaters in a device I want to make so this is why I am very interested in your opservation of this device

This information is giving an insight of how I am going to control these devices

But I going to use the 12 or 24 volt version of these devices

When I have the time and after I finish a project that I working on I am going to buy a few of them but one of them I going to do a forensic autopsy even though the device has has not failed

But I going to go at it as though it has failed to see how it made and it might give me an insight into why it behaves the way it does

[capwizard]

Re: hair straightener Soldering hotplate

but-but-but my friend I don't even know what is happening?

29.1c now, PTC is at 298.3k ohms I just barely touched it with my hand and it changed to 91.5k ohms @ 29.5 c then I connect it to the electricity for 3 seconds it goes down to 5.0 ohms.

[sam_sam_sam]

Re: hair straightener Soldering hotplate

This is a very good question, I have never thought of that.

first PTC is at 126.5 k ohms, heated for 3 sec. it changes to 51.9 k ohms if heated for 5 seconds it changed to 23 ohms! After 10 minutes PTC stayed at 3.2 ohms then I grabbed it with my hand, it changed to 27.6 k ohms. After 5 more minutes, it changes to 239.4 ohms.

This is the strangest thing I have ever seen. I mean...resistor. This PTC seems to be very sensitive to temperature.

diif... Can you confirm it with yours?

Thank you for posting your results this will help me a lot

[capwizard]

Re: hair straightener Soldering hotplate

This is a very good question, I have never thought of that.

first PTC is at 126.5 k ohms, heated for 3 sec. it changes to 51.9 k ohms if heated for 5 seconds it changed to 23 ohms! After 10 minutes PTC stayed at 3.2 ohms then I grabbed it with my hand, it changed to 27.6 k ohms. After 5 more minutes, it changes to 239.4 ohms.

This is the strangest thing I have ever seen. I mean...resistor. This PTC seems to be very sensitive to temperature.

diif... Can you confirm it with yours?

[budm]

Re: hair straightener Soldering hotplate

What is the cold resistance of that PTC @ 25c ? That will determine what spike current will be before the PTC resistance goes up.
Incandescent lamp is also has PTC.
http://lednique.com/technology-basics/bulb-basics/

[capwizard]

Re: hair straightener Soldering hotplate

I tried with Kapton tape. Still failed because Kapton tape does not transfer heat.

But I succeeded, I shorted and welded ac wire to an adjustable wrench.

it is funny because the PTC limited ac current to 0.5 A and it welded ac wire to the wrench. ( I have 15A breaker on it, nothing happens, this did not trigger it.)

What I mean is can we use PTC characteristics as an adjustable current limiter for a super simple AC welding machine?

[capwizard]

Re: hair straightener Soldering hotplate

I tried COF bounding and I failed. I need tempered glass.

It is very difficult to accurately locate the cof precise position.

Help?

[capwizard]

Re: hair straightener Soldering hotplate

I tried COF bounding and I failed. I need tempered glass.

[capwizard]

Re: hair straightener Soldering hotplate

it took 1 minute

[capwizard]

Re: hair straightener Soldering hotplate

I bought 2 x PTC @ 230 C. Actually 200 C is enough.

[diif]

Re: hair straightener Soldering hotplate

One question for diif is what kind of temperature PTC thermistor did you order? 250c or 200c

It's 260c. I have another that is listed as 250-260c.

[capwizard]

Re: hair straightener Soldering hotplate

The same principle can be proved Mr. diif's PTC heating thermistor will work on COF bonding also.

That's why I had ordered two small and narrow PTC thermistors for COF machine.

If someone uses PTC thermistor to make a soldering iron that will be wonderful you would not need any temperature controller and it will be as simplified as my sixth sense soldering iron.

One question for diif is what kind of temperature PTC thermistor did you order? 250c or 200c

[capwizard]

Re: hair straightener Soldering hotplate

Breaking news...... I used this hair straightener, successfully repaired LCD screen COF bouncing that I deliberately tore it open 1cm.

The next progression is on working TV.

The COF section connected to the screen is relatively close, more compact but the principle is basically the same.

.... so hair straightener portable COF bonding machine is in the future.

[diif]

Re: hair straightener Soldering hotplate

I've done some testing this week with mine from Ali.
Takes a couple of minutes to warm up but one up to temperature takes a couple of seconds to remove LEDs. I was surprised how well it works on the single sided FR4 strips as seen in some LGs. No burning or damage.

[sam_sam_sam]

Re: hair straightener Soldering hotplate

I personally would like it to have a temperature controller because I would want to use it other soldering projects

Some time if I had a section on a board that I am working on just to preheat it for a few minutes then work on that section because of a ground planes on a board

But that just me

I am thinking very seriously about building one and using a block of aluminum and have machined so that PTC is even with the block of aluminum with a ZD915 controller board because I have a temperature sensor that the soldering iron heat element went bad so I keep the sensor

I know someone who owns a machine shop that I off and on do work for to ask him do this for me

[capwizard]

Re: hair straightener Soldering hotplate

Thank you. I changed it to DC by adding one bridge rectifier it works if you want to use AC, yes you can, like diif said Aliexpress sale 230 Celsius element @ ac110v


110/220V PTC heating thermistors because of their unique characteristics you don't even need a switch, you can connect directly to the power outlet and they will always maintain the temperature range set by the manufacturer. This new technology makes the temperature control circuit very simple I mean none.