Mail Call #35: Audio Sockets and Jacks, Electret Microphones, Project Kits, and More | In The Lab

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This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

Silly Job Title: Cable Commander.

In this video we see what has arrived lately from AliExpress and Amazon:

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Yum Cha Mini Magnetic Precision Screwdriver SetThis is an image of the product.notes

Let’s go shopping!

Mail Call #34: Project Boxes, Power Adapters and Power Switches from AliExpress | In The Lab

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This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

Silly Job Title: Electricity Guardian.

In this video we take a look at what has arrived in the mail from AliExpress.

I mention about a project I’m working on: Electronics Project #13: Sanyo AM/FM Digital Clock Radio RM6018 Teardown Part 1.

Here is a list of the stuff that arrived:

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Yum Cha Mini High-Precision Electronic ScaleThis is an image of the product.notes

Let’s go shopping!

Destroying single disk ZFS zpool

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This is a note for Future John. I followed the instructions from ChatGPT. They looked reasonable enough. Now I have a spare 2TB SATA drive that has no purpose in life. I am always sad when things have no purpose in life. Who knows. Maybe one day…

-------------------
Tue Jul 01 03:33:54 [bash:5.2.15 jobs:0 error:0 time:0]
root@charisma:/home/jj5
# zpool status sata
  pool: sata
 state: ONLINE
config:

        NAME                               STATE     READ WRITE CKSUM
        sata                               ONLINE       0     0     0
          ata-ST2000DM008-2UB102_ZFL7BGR8  ONLINE       0     0     0

errors: No known data errors
-------------------
Tue Jul 01 03:34:00 [bash:5.2.15 jobs:0 error:0 time:6]
root@charisma:/home/jj5
# zpool destroy sata
-------------------
Tue Jul 01 03:34:08 [bash:5.2.15 jobs:0 error:0 time:14]
root@charisma:/home/jj5
# cat /proc/partitions 
major minor  #blocks  name
...snip...
   8       48 1953514584 sdd
   8       49 1953505280 sdd1
...snip...
-------------------
Tue Jul 01 03:34:23 [bash:5.2.15 jobs:0 error:0 time:29]
root@charisma:/home/jj5
# wipefs -a /dev/sdd
/dev/sdd: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41 52 54
/dev/sdd: 8 bytes were erased at offset 0x1d1c1115e00 (gpt): 45 46 49 20 50 41 52 54
/dev/sdd: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
/dev/sdd: calling ioctl to re-read partition table: Success
-------------------
Tue Jul 01 03:34:58 [bash:5.2.15 jobs:0 error:0 time:64]
root@charisma:/home/jj5
# sgdisk --zap-all /dev/sdd
Creating new GPT entries in memory.
GPT data structures destroyed! You may now partition the disk using fdisk or
other utilities.
-------------------
Tue Jul 01 03:35:28 [bash:5.2.15 jobs:0 error:0 time:94]
root@charisma:/home/jj5
# parted /dev/sdd --script mklabel gpt
-------------------
Tue Jul 01 03:35:50 [bash:5.2.15 jobs:0 error:0 time:116]
root@charisma:/home/jj5
# wipefs /dev/sdd
DEVICE OFFSET        TYPE UUID LABEL
sdd    0x200         gpt       
sdd    0x1d1c1115e00 gpt       
sdd    0x1fe         PMBR      
-------------------
Tue Jul 01 03:36:02 [bash:5.2.15 jobs:0 error:0 time:128]
root@charisma:/home/jj5
# lsblk /dev/sdd
NAME MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sdd    8:48   0  1.8T  0 disk 
-------------------

New Book Teardown #7: Electricity and Magnetism 3rd Edition (2013) | In The Lab With Jay Jay

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This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

Silly Job Title: Prime Hack.

In this video we tear down Electricity and Magnetism 3rd Edition written by Edward Purcell and David Morin and published in 2013.

Electricity and Magnetism is one of the books I am taking notes for as a part of my Learning the Art of Electronics project. These notes are a perk for people who support me on Patreon, so what are you waiting for!? :)

There is a website for the book maintained by the publisher, but regrettably there’s not much there, just some material available to instructors only: https://www.cambridge.org/Purcell-Morin

I mention two xkcd comic in the video, those are these: Farads and Nerd Sniping.

The “esu” is prounounced as “eee-ess-you” and is also known as the Statcoulomb.

I mention the Franck–Hertz experiment which happens to be something I wrote a Hackaday article about: A DIY Version Of The Franck-Hertz Experiment.

The first edition of Electricity and Magnetism was volume two in a five volume course: Berkeley Physics Course.

The books mentioned in Chapter 1 include The Flying Circus of Physics and How Things Work.

The websites mentioned in Chapter 1 are:

The Feynman (1977) reference is to The Feynman Lectures on Physics which is also available here: www.feynmanlectures.caltech.edu

The symbol: ∇ (“nabla”, an upside down Δ “delta”) is the vector differential operator and its key uses are:

  • ∇f → gradient of scalar
  • ∇·F → divergence of vector field
  • ∇×F → curl of vector field
  • ∇² → Laplacian

The Big Clive video that I mentioned was this one: How a stungun creates 20kV from a 9V battery.

I also mention the show’s wiki, the ITL Wiki, which is on the web over here: https://www.inthelabwithjayjay.com/wiki/

Thanks very much for watching! And please remember to hit like and subscribe! :)

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

AIRAJ 3-Pcs 7-inch Locking PliersThis is an image of the product.notes

Let’s go shopping!

New hard drives

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Yesterday I was talking to my friends on IRC about how I should use a proper RDBMS for ad hoc data analysis more often. Then I found myself a job.

The hard disks I use for my offsite backups are ready to be replaced. They are good reliable drives (Western Digital Ultrastar 8TB) but they have been in service for five years and the warranty is just about to expire.

So I wanted to get some new drives which will do me for the next five years. I needed to know: what are good reliable drives to buy?

It turns out Backblaze maintains Hard Drive Data and Stats.

I downloaded their data for Q1 2025 and wrote a few scripts to process it. The output was this report:

Report on hard drive failures

The first drive listed in the above report is an SSD, but I want an ordinary spinning rust HDD. The second drive listed is ST12000NM000J which is Seagate Exos X18 12 TB. I found them on Amazon for AU$499 and on eBay for AU$280. So I purchased three drives from eBay.

Time well spent. Thanks d0nk`! <3