| Electronics > Beginners |
| Mini TS100 soldering iron and current leakage |
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| stj:
i think the ts100 does link the shaft of the cartridge to the earth screw and probably the input-jack. btw, if your going to build a controller then you may as well build that one - it's the simplest i'v seen. you can skip the gyro chip to make it even simpler. |
| stj:
yes, lower-right of the schem. j1 coupled to main ground via c26. interesting. it wont pass dc, so no accidental discharging of big caps while soldering!! >:D |
| KL27x:
Well i am not much good at this, but it looks like A and B are connections to either end of what would be the heater. If u look at the cartridge, u will see two ring contacts at the end away from the working tip. I assume these are A and B. And the rest of the cartridge metallic surface that includes the tip wouod be what should be earthed in an ESD safe iron according to IPCS or however u spell/acronym? J1 at the bottom right shows a capacitor btn PGND and B. Which i am confused because B doesnt seem to be the tip, and capacitor wouldnt earth it even if pgnd was earthed. |
| KL27x:
So my understanding is perhaps not full, here. I might have to shelve my controller dev until my T12 handpiece and tips get here. The way I am guessing is that power is applied through A and B ring contacts, then cut, then a TC output of uV can be measured between A and B. But this implies that you can send several amps through the TC without damaging it, and I don't even know if that is possible. I don't know what the voltage drop and resistance of a TC is nor if you can do that without damaging it. In theory it's just two different metals welded together, so it seems like it should be possible to just use it as a conductor when not reading it. A > heater wire > TC > B ??? If my idea works, my Hakko 888 will be able to drive a T12 tip with up to 17% more power than an actual Hakko 951. And 70% more power than a DC laptop supply clone at nominal 20VDC max (without even including the pauses for reads needed in the DC version). |
| stj:
o.k. i was a bit wrong. the cartridge is earthed, the wrist-strap is decoupled through a cap. your operational theory is right, the thermocouple is in series. you power the element, then cut the power & read the voltage on the same pins. then if it's under the set temp - power it up again. this is the place it all comes from. http://minidso.com/forum.php?mod=forumdisplay&fid=67 |
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