I find 0402 still manageable.
MSOP (0.65mm pitch) is OK with lots of flux and solder wick. The lead-less stuff and 0201 is a real challenge for hand soldering, though.
Good tools are needed (needle solder tip, precision tweezers), with the most important being surgeon's binoculars and good light for me these days.
MSOP (0.65mm pitch) is OK with lots of flux and solder wick. The lead-less stuff and 0201 is a real challenge for hand soldering, though.
Good tools are needed (needle solder tip, precision tweezers), with the most important being surgeon's binoculars and good light for me these days.
I’m not a fan of anything head worn. A decent stereo microscope is worth every penny if you’re using it even occasionally.
Yes but I need something that keeps me mobile. Like this:
US Dental Binocular Loupes Surgical Glass Magnifier + LED Headlight 3.5X Optical 190891656735 | eBay
Jan
I'm using Eschenbach Rido-Med models #16362 (2.5x) and16364 (4x):
https://i1admin04.webstorepackage.c...ridoMED-teleMED (11446, 1634..., 1636...).pdf
Often can be found for way less than the ~380€ list price
It takes a while to get used to them but after a while you don't want to miss them anymore...
Also I'm comfortable with wearing 5x and 7x watch maker's magnifiers, Eschenbach #11245 and 11247 which are very cost effective at 10€. Just take care of you nose when soldering ;-)
PC-connected USB microscopes are also becoming better and cheaper these days...
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Klaus I am concerned about the weight of this on my nose and ears with prolonged wearing. That is why I was looking at something with a headband.
Is that not an issue?
Jan
There is no indication (in any of the sims) that this is true, the sims even show a slight elevation of the OLG (that is the sims with real amps and with the gain modules (E)). The actual load of the amplifier will be very low, we are talking mV's (as a maximum) thus a few 100's of uA's max.
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I have an el cheapo head set, with different zooms, it is a bit hard on the head, after a while, but it is very light, I have used them to do DFN's and other 0.5mm pitch. A1lso use the 10x jeweler loupe, it works great for inspection and if I prop it up properly I can solder using it. Can not remember where I got it, ebay maybe, parts Express? I'll look.
I know my Dentist has a beautiful set, but we are talking >1000US I would think. Interesting to look/shop around
In the old days at HP, we had a Leica stereo microscope with a small circular lamp, it worked fine too, but I can not justify that at home for the little that I do.
Digi-key 243-1197-ND, 243-1193-ND
Surgical Loupes, Dental Loupes, Magnifying Loupes | Orascoptic
I know my Dentist has a beautiful set, but we are talking >1000US I would think. Interesting to look/shop around
In the old days at HP, we had a Leica stereo microscope with a small circular lamp, it worked fine too, but I can not justify that at home for the little that I do.
Digi-key 243-1197-ND, 243-1193-ND
Surgical Loupes, Dental Loupes, Magnifying Loupes | Orascoptic
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Frans, it may or may not show up in sims, depending on model accuracy. But this opamp has a common emitter output stage (the collectors are the output) and the OL gain is directly depending on the load they need to drive, which should be clear by simple inspection.
Of course, with enough feedback you can try to hide it but no doubt it will adversely affect performance.
I remember a very old article in Wireless World where this was researched. Not sure I can find it.
Jan
Argh, I found the files, they are pdfs generated years ago, which the current Adobe reader cannot decode (in particular the equations part). I'll need some time to try to rebuild the files from my old hand notes.
Never mind, found the original .docx files and saved again as pdf. These were written in the context of implementing a power amplifier with deep under ppm distortions. There's a 3rd part (measurements), I'm still looking for it in my archives.
He may or may not be
but the output impedance of the OPA211 is not the limiting factor.At an output current of 100 uA in 10 Ohm (that is at 1mV output voltage) and given a Vpp of 5V the effective (required) output impedance will be 50 kOhm. (way above the specified 5 Ohm).
Any way this is my last post about this subject, there is a good possibility that the 10 Ohm resistor may replace the diodes network. What is wrong in tying, I never said that it will be guarantied to work, I always said it may work, what is the problem in doing the test and spend the 10 Ohm resistor.
You (all) should remember that the only thing I wanted to do is to suggest an alternative way of preventing the amplifier to lock-up or -down. Using the 10 Ohm resistor may or may not work, but is it works, the circuit will be simpler, cheaper and occupy less board area, what is there not to try?
P.s. The power amplifier that you find in my signature(linked) is a composite amplifier delivering up to 400W into 2Ohm (measured by an independent laboratory) Jan knows
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