Home
Help
Search
Login
Register1
Projects, Designs, and Technical Stuff / Re: One Capacitor Type to Rule Them All? Help?
« Last post by NT0Z on Today at 03:26:32 am »In a perfect world that's true. But this is far from the craziest idea I've had! 
--NT0Z
--NT0Z
Recent Posts
2
Projects, Designs, and Technical Stuff / Re: One Capacitor Type to Rule Them All? Help?
« Last post by NT0Z on Today at 03:24:56 am »Yes, I don't need bypass caps to be NP0, etc, and I have thousands of those in my junkbox already. I tend to use through-hole parts and SMD parts together, all on one side of an SMT board or Manhattan-style on a piece of copper-clad board.
I am looking into some kind of affordable USB assembly scope/stand with an LCD display. My eyesight isn't great for binocular solutions, as my left eye is awfully ornery. I use a magnification app as necessary on my Android phone, which is fantastic, but the camera lens aims down and the screen aims up, which is about 90 degrees away from useful when trying to solder. For inspection, no prob.
Although embracing it after 45 years, I do not have much experience with SMD. My trial by file was to replace SOIC8 and SOIC20 chips on the PCB of an obscure GPSDO unit. It worked (golf clap inserted here!) but it was really pushing my neurology. I have the aforementioned ornery left eye, a recalcitrant right eye, and ulnar nerve damage in my right (master) hand. What I really need is an SMD assembly robotic fixture from 20 years into the future!
I guess it comes down to wanting a good supply of "widely usable" parts on hand so I don't have to wait for delivery every time I want to build something (and pay shipping, and shipping, and shipping). I have lots of Rs, plenty or toroids to make Ls, and I have lots of through-hole Cs. I am hoping that I can sort of standardize on NP0/C0G 1206s for HF/RF stuff.
I recently ordered a couple hundred 600-V caps in the usual values for restoring tube amps and radios. Now, when I need something along those lines I have a pile of 'em on hand. Setting aside bypass caps, electrolytics, and audio stuff such as tantalums, I'm hoping that laying in a supply of NP0s will get me squared away for oscillators, filters, etc.
Plus, it's still shocking how little space SMD parts-caches take up!
Thanks for all of the advice. I appreciate it,
--NT0Z
I tend to use through-hole parts and SMD parts together, all on one side of an SMT board or Manhattan-style on a piece of copper-clad board.I am looking into some kind of affordable USB assembly scope/stand with an LCD display. My eyesight isn't great for binocular solutions, as my left eye is awfully ornery. I use a magnification app as necessary on my Android phone, which is fantastic, but the camera lens aims down and the screen aims up, which is about 90 degrees away from useful when trying to solder. For inspection, no prob.
Although embracing it after 45 years, I do not have much experience with SMD. My trial by file was to replace SOIC8 and SOIC20 chips on the PCB of an obscure GPSDO unit. It worked (golf clap inserted here!) but it was really pushing my neurology. I have the aforementioned ornery left eye, a recalcitrant right eye, and ulnar nerve damage in my right (master) hand. What I really need is an SMD assembly robotic fixture from 20 years into the future!
I guess it comes down to wanting a good supply of "widely usable" parts on hand so I don't have to wait for delivery every time I want to build something (and pay shipping, and shipping, and shipping). I have lots of Rs, plenty or toroids to make Ls, and I have lots of through-hole Cs. I am hoping that I can sort of standardize on NP0/C0G 1206s for HF/RF stuff.
I recently ordered a couple hundred 600-V caps in the usual values for restoring tube amps and radios. Now, when I need something along those lines I have a pile of 'em on hand. Setting aside bypass caps, electrolytics, and audio stuff such as tantalums, I'm hoping that laying in a supply of NP0s will get me squared away for oscillators, filters, etc.
Plus, it's still shocking how little space SMD parts-caches take up!
Thanks for all of the advice. I appreciate it,
--NT0Z
3
Test Equipment / Re: Rebranding of multimeters?
« Last post by Bobson on Today at 03:06:39 am »
Sonel, a Polish Company are another own manufacturer, I cannot place who makes their multi-meters or if they are their own design.
A lot Sonels are rebadged CEM.
4
Test Equipment / Re: Rebranding of multimeters?
« Last post by Bobson on Today at 03:02:54 am »APPA is the manufacturer of Ideal, Greenlee, Iso-Tech, Jensen, Westward, Benning, some Tektronix and Megger meters, plus other brands.
The way I understand it, at least in the past, APPA was making multimeters for Tektronix but they were a Tektronix design.
At least some Tektronix DMMs were designed and made by Escort (later bought by Agilent).
5
Repair / Re: HP54600B with spike problem with and without signal
« Last post by T3sl4co1l on Today at 03:01:02 am »The 1SL7- is an HP proprietary ASIC; it's basically only going to be available as replacement, or salvage from other boards. (All the more reason to make sure everything is fine first..!)
Tim
Tim
6
3D printing / Re: Resize a STL File For Me
« Last post by bostonman on Today at 02:53:52 am »Sorry, I used the term 'rotation' and meant 'revolution' (located in the design drop down menu). At one point I tinkered with revolution, and, when I accomplished a groove pattern, wondered if a difference exists.
I assumed the groove "reference" was the vertical part of the groove pattern, however, if this is an outdated method and revised in later versions, no sense pondering on the topic.
Quote
I was able to reference the X-Z plane directly. You have a more ways of creating reference planes in the newer versions.
I assumed the groove "reference" was the vertical part of the groove pattern, however, if this is an outdated method and revised in later versions, no sense pondering on the topic.
7
Beginners / ASUS A2500D Laptop, how to access the CMOS battery??
« Last post by CaptDon on Today at 02:52:51 am »I can't find any useful information on the internet. The unit works but I have to hit F2 to accept the default CMOS settings, F10 to save and exit and it boots fine. I'd like to replace the CMOS battery but can't locate it. I found the RAM modules under the keyboard and the hard drive is an easy swap. Thanks for any links or info!!
8
Repair / Re: What is the exact model of this transistor?
« Last post by daisizhou on Today at 02:48:27 am »Q209 and Q208 seem to be like this, but my fault still exists.
9
General Technical Chat / Re: Cheapest way to get date/time from GPS
« Last post by fourfathom on Today at 02:47:48 am »Recently i commented about a RTC test using a STM32 Nucleo-L476. I estimated the out of the box frequency offset as about 10 ppm.
Meanwhile i connected a ublox 6M GPS module to the board and implemented capture of its one second pulse output using timer 1 running from LSE with a 32768 cycle (channel 3). Then i implemented frequency measurement over spans of 65 seconds (linear regression of captured timings). The diagram shows the measured frequency offsets over about 4 hours in units of the RTC smooth calibration unit = 0.954 ppm. Average offset is 9.764 ppm with a standard deviation of 0.031 ppm.
So the clock noise can be as little as one second per year.
I don't know much about the STM32, but FYI I was running a SAMD controller off it's internal oscillator (no xtal) and marveling at how accurate and stable it was.
Uh, no.
I had the controller hooked up to USB, using USB serial to communicate. Turns out that the USB is used to monitor and adjust the internal uC clock. When I unplugged the USB connection the internal clock became pretty awful. It was in spec, no problem there, but the amazing accuracy was no longer so amazing.
10
Projects, Designs, and Technical Stuff / Re: Suggestions for secure authentication solution?
« Last post by DrGeoff on Today at 02:26:16 am »What's the comms protocol? It sounds like you control both ends, so I assume you also have control over the messaging protocols and formats (APDU)?
You may be able to build the security into the messaging protocol using pre-placed symmetric keys (eg AES-256) and include the selected key number in the header of the message.
The use of small 8-bit devices in endpoints allows the use of symmetric algorithms such as AES quite easily.
You may be able to build the security into the messaging protocol using pre-placed symmetric keys (eg AES-256) and include the selected key number in the header of the message.
The use of small 8-bit devices in endpoints allows the use of symmetric algorithms such as AES quite easily.