Undervoltage Problem
All, Here's a real world example of damaging undervoltage: I once built a RTTY TU ( Terminal Unit ). The teletype had a "loop" consisting of a 120VDC power supply feeding a resistor and going to the
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[email protected] <jerry@...>
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#88158
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Re: Undervoltage Problems
CMOS input pins typically have on chip Schottky protection diodes to both the Vdd rail and to ground, so any input signal above Vdd or below ground gets clipped by those diodes. If the driver into
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Jerry Gaffke
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#88157
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Re: Undervoltage Problems
Indeed. That's the power supply sequencing issue I mentioned in an earlier post.
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Jerry Gaffke
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#88156
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Re: Undervoltage Problems
If the voltage to the display is lower than the voltage to the micro, the voltage on the input pins on the display could be higher than the supply voltage to the display, then there is a problem that
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Stig oz8pz-oz8wsp-oz8wsr
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#88155
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Re: R1.4.0 Software Release
#ubitx
#nano
#v6
#ubitxv6
Great to hear! Thanks, Dennis! Reed
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Reed N
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#88154
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Re: Undervoltage Problems
I'm still catching up on this thread. Robert AG6LK wrote: "I'm not sure why there could be damage to a display if the voltage dropped. On the enclosed paperwork, that came with the Nextion 5¡±
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Jerry Gaffke
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#88153
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Re: Undervoltage Problems
It may be possible to design a logic gate that works fine at 5v, and self destructs at 4v. Such a product would not sell very many units.
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Jerry Gaffke
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#88152
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Re: Undervoltage Problems
A low power supply voltage can cause electronics to do unexpected things. but pretty much never causes damage.? ?When bringing up a new board,? you are far more likely to cause damage by bringing
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Jerry Gaffke
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#88151
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Re: uB v3 on ebay
It's already up to $52 plus shipping. I have an untouched, unbuilt v3 still in the shipping box. Never opened, never touched by a soldering iron. What would be a fair price? Any interest here? Clay
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Clay Nicolsen
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#88150
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Teensy 4.1
#ubitxv6
Anyone wanting the TSW Teensy 4.1 Raduino kit, they are still available.? We have located a source of 5351 clock/VFO chips and it turns out that Mouser electronics, at least, has over 700 Teensy
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Jim Sheldon
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#88149
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Re: R1.4.0 Software Release
#ubitx
#nano
#v6
#ubitxv6
Reed, I want to thank you for the excellent job you did on the manual. It was easy to read and the steps for updating the firmware were easy to follow. I ran into no hitches even though I had no
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Dennis Roth N3AZB
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#88148
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Re: Undervoltage Problems
Great write up Reed, This deep work and you explained it so well. Like me, I am sure many of us here have picked up so much from it all. I was always curious of how the totem pole worked with varying
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Ashhar Farhan
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#88147
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Undervoltage Problems
Over at /g/BITX20/topic/ubitx_v6_specifications/82557868 I saw some folks wondering how in the world something could be damaged by undervoltage, since as we all know, when things are
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Reed N
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#88146
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Re: uBITX V6 Specifications.
Hi all, Thank you for all for your information and comments. Bill, I'm not sure why there could be damage to a display if the voltage dropped. On the enclosed paperwork, that came with the Nextion
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Robert AG6LK
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#88145
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Which 5" Nextion display to buy
Bought a very nice chassis and ordered a ver 6 board. Looking to buy a 5" Nextion display....what is the best model number? I see a few choices on amazon. Thank you - Mike
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Kj7OCO
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#88144
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Re: uB v3 on ebay
At this price... Go for it, it¡¯s not even the price of spare parts. There may be only one transistor to change?? Too bad no shipping to France.
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Gerard
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#88143
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Re: uBITX V6 Specifications.
Thanks, I will be doing that. Earl Cox? KB5UEW?Reply or E-mail me at:? kb5uew@...
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Earl Cox <kb5uew@...>
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#88142
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Re: technical question about filter capacitors
I would not have posted anything, were I not satisfied with the product...likely not much good for small values of caps (but what is ?)...works just fine for 10 nF and stuff in that area Jim
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jim <ab7vf@...>
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#88141
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uB v3 on ebay
Someone's selling a uBitX V3 in a case on ebay. At this time the bidding is only at 12.50. Not mine, just sharing the info. https://www.ebay.com/itm/265148896485 Vince. -- K8ZW
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Vince Vielhaber <vev@...>
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#88140
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Re: uBITX V6 Specifications.
I won't say for sure, but possibly some devices may draw excessive current if the voltage is too low.? I happen to know that some motor-driven equipment will be damaged by under-voltage.? The motor
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Gerald Sherman
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#88139
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