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Make and model of the laminator? I just ordered a "Royal Sovereign 9" Desktop Laminator" from Office Max for doing toner transfer. -- Paul Mateer, AA9GG Elan Engineering Corp. www.elanengr.com

I've been persisting for a couple of months trying to get really good boards using photo resist. I prefer the dry film method because poorly exposed boards can be stripped and recoated quite easily,

No issues. Thanks for reply All the best

I have no clue. When I first saw it, I thought you quoted it, but forgot to add some comments. Probably a glitch on the forum. Dave

How come my name is shown across this post! I dontvremember to have replied this post on 11th nov. I would appeal the site manager to please check the original poster . Regards sarma

Semiconductor devices can be surprisingly good at protecting fuses. <humour intended> Donald. -- *Plain Text* email -- it's an accessibility issue () no proprietary attachments; no html mail /\

On Mon, 11 Nov 2019, 9:06 pm Dave, <theschemer@...> wrote: > Hi Harvey, > > In my case I am just using the USB port for handy readily available > power to run IR Led's so it is the simplest

Hi Harvey, ? In my case I am just using the USB port for handy readily available power to run IR Led's so it is the simplest circuit. They have a .100 mA max spec for amperage and I can run them at

Yep, from what I read, the trip current vs time to trip is a lot longer than for fuses, the advantage being only that they reset. From what I can see, they're best used in catastrophic failure cases

Hi Harvey, ? According to the LittleFuse datasheet, PTC fuses are used to protect: USB peripherals Disk drives? CD-ROMs Plug and play protection for motherboards and peripherals Mobile phones -

Thanks Donald. I never ran across that Wiki article even though I was looking for some answers on this. Still seems like a long time though to get back to normal status. Made me think of "muscle

The mechanism of the resettable fuse PTC is thermo-mechanical. When heated, the resistive elastomeric elements expand, increasing the length of the resistive elements. It can take a very long time,

Thanks Jan, ? That is a good way of looking at it. I just wonder why it takes hours/days at room temp too come back down to/towards 1.5 ohms. That said, my circuit will likely never see that fuse

I would treat the PTC as a very loose-tolerance resistor. Make sure your circuit will work properly if the PTC resistance is anywhere between 1.5 and 10 ohms. It's probably close to 10 ohms soon after

I spent a little time looking at PTC fuses. Made the following observations: 1) their resistance is higher than a regular fuse (and a fuse *must* have a resistance) 2) the best use of the fuses is

Brad, Thanks for the test procedure. The PTC's I am going to have to test are .100mA hold and .250mA trip. I should be able to figure it out but if not, I will ask for some more help. :) Dave

Dave wrote on 11/8/2019 4:30 PM: Hello, Dave-- It should be possible to create a more elaborate test.? The basic idea is to explore the DUT's recovery time and series resistance. Connect the

Hi Brad, Makes sense but I am hoping that in practice it is closer to 1.5 ohms, and after it heats up, it cools back down to the same spec (1.5 ohms) each time. If not, I have to do some redesigning.

Donald, Thanks for confirming what I thought. That makes sense. This is a self resetting fuse. I guess I can test the parts with heat and see what they cool down to after they have been tripped using

Dave wrote on 11/8/2019 11:17 AM: Hel