Skip to content

Electrical Component Cross Sections

March 30, 2019
Take a look at these fascinating and educational cross sections of an LED, resistor, diode, capacitor, and more. (The images in this Moment created by TubeTimeUS are licensed under CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/)
Photo via @TubeTimeUS
· Apr 2

here's a cross section of an Ethernet transformer. inside a network adapter, there is one of these in between the Ethernet PHY chip and the cable, providing isolation and safety.

8 replies 35 retweets 229 likes
· Apr 2

here's the side view cross section of an Ethernet transformer.

1 reply 7 retweets 82 likes
· Apr 2

annotated version of the Ethernet transformer cross section.

1 reply 14 retweets 97 likes
· Apr 2

ok don't try this one at home: this is a cross section of an LR44 alkaline button cell! 🔋⚡️

7 replies 14 retweets 151 likes
· Apr 2

annotated cross section of the LR44 alkaline button cell.

1 reply 15 retweets 68 likes
· Apr 3

inspect this cross section of a BGA-packaged chip.

9 replies 26 retweets 196 likes
· Apr 3

annotated cross section of a BGA-packaged chip.

3 replies 17 retweets 98 likes
· Apr 3

detail showing the vias in the substrate

2 replies 10 retweets 102 likes
· Apr 3

ever wondered what's inside an optocoupler? wonder no more--look Kat this cross section!

10 replies 39 retweets 261 likes
· Apr 3

...and here's the annotations for the optocoupler cross section.

10 replies 37 retweets 196 likes
· Apr 3

diodes may look simple, but there's subtlety inside them. check out the cross section of this 1N914.

10 replies 77 retweets 376 likes
· Apr 3

here's the annotated cross section of the 1N914 diode. the two Dumet slugs are separate pieces of metal from the leads, and are brazed together during manufacture.

2 replies 13 retweets 82 likes
· Apr 3

look at the slug on the left--you may notice it has a taper at the end. i think this end is inserted last, pushing up against the ohmic contact (dot) that's already plated onto the silicon die. then when it is heated to bond the glass to the dumet, it alloys with the contact.

1 reply 1 retweet 26 likes
· Apr 3

how does the dot get there? there's a plating bath that applies an AC voltage that's slightly above the diode's voltage rating. only the good diodes get a dot at the cathode end. bad ones break down and plate on both sides. this means they are heavier...

1 reply 4 retweets 34 likes
· Apr 3

...to sort out the bad diodes from the good ones, they dump the whole lot into a very dense fluid. the bad diodes sink, and the good ones float, so they just scrape those off and use them. forget what fluid they use, it's apparently quite toxic. barium something-or-other?

4 replies 4 retweets 43 likes
· Apr 3

the sleeves start out with one slug already installed. these all go into special trays. the diode chips are dumped across the tray which is then vibrated at a very specific frequency, causing the diodes to land dot side up!

1 reply 2 retweets 41 likes
· Apr 3

(source: friend of mine who used to be involved with diode manufacturing way back in the day)

1 reply 2 retweets 33 likes
· Apr 4

cross section of a headphone plug and jack (aka 1/8" or 3.5mm phone plug). you can see the jack has switches in it. these are often used to disconnect an internal speaker.

16 replies 266 retweets 1,090 likes
· Apr 4

annotated version of the headphone plug and jack cross section.

5 replies 99 retweets 351 likes
· Apr 4

this is a small audio transformer, but cut in half and polished.

3 replies 10 retweets 101 likes
· Apr 4

let's zoom in a bit. now you can see the individual strands of copper!

2 replies 6 retweets 67 likes
· Apr 4

cross section of a small audio transformer, zoomed in and annotated.

3 replies 14 retweets 75 likes
· Apr 5

here's a 5mm wide surface mount power inductor that's been sanded down to expose the insides!

4 replies 28 retweets 272 likes
· Apr 5

and here is the SMD power inductor with annotations. since this is a shielded inductor, it has an outer ferrite shield that helps contain the magnetic field. this reduces the stray magnetic fields which could interfere with other components.

3 replies 11 retweets 89 likes
· Apr 6

this is a small PCB-mount magnetic speaker that i've cross sectioned.

6 replies 18 retweets 190 likes
· Apr 6

here's the annotated cross section of the PCB-mount magnetic speaker.

5 replies 16 retweets 85 likes
· Apr 6

check out this cross section of a bi-color red/green LED! you can see that there are two LED die and two bond wires.

16 replies 50 retweets 377 likes
· Apr 6

this is the annotated version of the red/green bi-color LED cross section.

1 reply 17 retweets 112 likes
· Apr 6

this is a cross section of a 7-segment LED display. you can see the tiny LED chip!

3 replies 24 retweets 175 likes
· Apr 6

annotations calling out the various parts of this cross sectioned 7-segment LED display.

3 replies 23 retweets 88 likes
· Apr 6

the LED segment still lights up!

1 reply 6 retweets 124 likes
· Apr 7

this is a 3-pin bi-color LED that's been sanded down so you can clearly see the lead frame and LED chips.

14 replies 154 retweets 874 likes
· Apr 7

with annotations.

2 replies 12 retweets 92 likes
· Apr 7

close-up of the two LED chips. one is shorter than the other.

3 replies 7 retweets 81 likes
· Apr 7

cross section of an electret microphone element. 🎤

7 replies 27 retweets 214 likes
· Apr 7

annotated cross section of an electret microphone element. 🎤

2 replies 13 retweets 78 likes
· Apr 7

you can see the electret film coating on the backplate here. the metallized diaphragm is torn and distorted from the sectioning process

1 reply 1 retweet 30 likes
· Apr 7

how it works: the metallized diaphragm and backplate act as the two plates of a parallel plate capacitor. the electret material sits in between, along with a small air gap. the electret gives this capacitor a constant charge, Q...

1 reply 23 likes
· Apr 7

...and since the capacitance changes when the diaphragm deflects due to sound coming in because C = e0*A/d, and because Q = CV, the voltage V = (Q/Ae0) * d. in other words, the voltage is directly proportional to the change in distance between the two plates.

1 reply 1 retweet 23 likes
· Apr 7

the most fascinating part is the magical electret material. the name is a portmanteau of "electrostatic magnet." it's a material made of polar molecules (positive charge at one end, negative charge at the other) which are all aligned.

1 reply 4 retweets 51 likes
· Apr 7

basically you melt the material while it's in a high voltage electric field, causing all the polar molecules to line up, then you let it cool and solidify. now one side is positively charged while the other side is negatively charged. 🧙‍♀️🧲⚡️

1 reply 2 retweets 54 likes
· Apr 7

tried a suggestion from and put a little oil on it to clear up the surface a bit. it helped a bit, but now there are tiny bubbles. 😂

2 replies 6 retweets 64 likes
· Apr 7

wow, this bi-color LED is even more beautiful from a slightly different angle!

4 replies 51 retweets 310 likes
· Apr 7

ooh 😍

8 replies 52 retweets 387 likes
· Apr 8

ever wonder what a 0.1" header and socket look like inside when they're plugged together? wonder no more, rest your eyes on this cross section!

15 replies 68 retweets 560 likes
· Apr 9

this is a cross section of a miniature reed relay. they're used by the millions in semiconductor test equipment, then discarded after a million cycles, which happens sooner than you might think!

6 replies 17 retweets 159 likes
· Apr 9

this is the annotated cross section of the miniature reed relay. there's a digital cycle counter in the test equipment these are used in, and when that counter passes 1,000,000, the relays are unplugged and thrown out!

2 replies 16 retweets 74 likes
· Apr 9

here's what the relay looks like, intact, resting comfortably on George. often a semiconductor test board will have one of these relays per pin, and sometimes more.

3 replies 4 retweets 49 likes
· Apr 10

cross section of a PCB-mount slide switch. this one is SPDT. these are quite inexpensive switches!

8 replies 24 retweets 202 likes
· Apr 10

here's the annotated cross section of a PCB-mount slide switch. when you push on the actuator, the rocker forces the ball against the spring. the ball rolls over the rocker, applying force to the opposite side, moving the rocker so that it presses up against the opposite contact.

3 replies 13 retweets 92 likes
· Apr 11

check out this cross section of a plain old DIP switch. there are 4 switches in this one, and this is one of the switches.

4 replies 22 retweets 241 likes
· Apr 11

here's the annotated version of the DIP switch cross section. it's pretty simple! note that the actuator has two detents simply because it's a symmetrical plastic piece that can be installed in either orientation. only one detent is used.

1 reply 17 retweets 95 likes
· Apr 12

this is a very cheap pushbutton that i've cut in half so you can see how simple it is inside. please ignore the void in the middle of the spring; i use glue to hold the internal parts in place during sectioning.

6 replies 10 retweets 130 likes
· Apr 12

here's the cheap pushbutton switch cross section with annotations.

3 replies 23 retweets 84 likes
· Apr 12

ever wonder what a D-sub connector looks like inside? here's a cross section of a DE-9 plug and receptacle.

21 replies 200 retweets 930 likes
· Apr 12

naturally i also made an annotated version of this picture so you can tell what's going on. there are a few subtle features of the design, like the tiny little solder dams that prevent solder from wicking up inside the pins and sockets.

3 replies 39 retweets 193 likes
· Apr 16

this is a cross section of an electrical component that interacts with you every day! in fact, there's a good chance you've got one very close to you even as you read this. what is it?

14 replies 14 retweets 133 likes
· Apr 16

it's a vibration motor! this is the annotated cross section. (there's a little air bubble in the upper right that formed in the glue i used to hold it together for the sectioning process.)

1 reply 3 retweets 62 likes
· Apr 18

cross section of a 2N2222 in a TO-18 metal can

19 replies 108 retweets 612 likes
· Apr 18

here's the annotated version of the 2N2222 in the TO-18 package. the package is actually pretty complicated! lots of materials science here.

6 replies 35 retweets 193 likes
· Apr 18

from this angle you can see the 2N2222 transistor die. 👾

15 replies 53 retweets 368 likes
Play
Hover to unmute
0:04
· Apr 20

the transistor lights up like an LED! it happens if you reverse bias the base-emitter junction and trigger an avalanche breakdown (about 10V). h/t for the technique.

4 replies 31 retweets 177 likes
· Apr 18

this is a cross section of a quartz crystal in an HC-49 package. ignore the blob of glue on the right, it was to hold the quartz in place during sectioning.

5 replies 16 retweets 144 likes
· Apr 20

here's a cross section of a BLOWN LED. why is it so clean? IT CROSS-SECTIONED ITSELF. i have video proof to follow!

11 replies 36 retweets 252 likes
Play
Hover to unmute
0:04
· Apr 20

video of an LED failing and cross-sectioning itself right down the middle! 🤯

4 replies 15 retweets 88 likes
· Apr 20

annotated version of the LED that failed and cross sectioned itself.

2 replies 14 retweets 86 likes
· Apr 22

SMA connectors help move RF signals from place to place. here's an SMA mated connector pair cut in half. they are from two different manufacturers, but fit together perfectly -- tight tolerances are critical for good RF performance!

12 replies 117 retweets 457 likes
· Apr 22

annotated cross section of a mated SMA connector pair. this annotation barely scratches the surface because there are a lot of very subtle design features that you'd need a whole class to cover.

8 replies 48 retweets 164 likes
· Apr 22

this is a type N connector cut in half. the 'N' stands for Neill, since Paul Neill worked on this connector while at Bell Labs. he also worked on the BNC connector (Bayonet Neill-Concelman).

7 replies 65 retweets 317 likes
· Apr 22

this is an annotated cross section of the type N connector. notice the distance between the center conductor and the ground shield changes depending on the dielectric material (air or plastic).

2 replies 30 retweets 125 likes
· Apr 23

this is a common BNC plug and jack that have been cut in half. it is quite a complicated and subtle assembly!

6 replies 43 retweets 227 likes
· Apr 23

here is the annotated BNC plug and jack cross section. notice that the diameter of the center contact is consistent and only changes when it enters the cable, which is when the dielectric diameter changes as well? this is to maintain a constant 50 ohm impedance.

4 replies 20 retweets 106 likes
· Apr 23

it's fascinating to compare the 75 ohm and 50 ohm BNC connectors! the contacts are the same size to prevent damage when accidentally mating 75 ohm to 50 ohm connectors. to keep the 75 ohm impedance, the connector uses an air gap around the wider contacts.

7 replies 46 retweets 186 likes
· Apr 24

here's a slightly unusual connector. this is an HDBNC (High Density BNC) connector that's been cross sectioned. it's sometimes used for video broadcast equipment (75 ohms) but this example is 50 ohms. the second image compares it with standard BNC.

4 replies 10 retweets 135 likes
· Apr 24

cross section of the HDBNC connector. there are a bunch of air gaps, dielectric thickness changes, and complex features that are telltale signs of computer modeling and simulation.

2 replies 7 retweets 70 likes
· Apr 29

this is the cross section of a coaxial cable. it's a LMR-195 cable which is pretty similar to RG-58

9 replies 13 retweets 143 likes
· Apr 29

annotated cross section of the LMR-195 cable.

3 replies 8 retweets 77 likes
· Apr 29

cross section of a common USB cable.

19 replies 130 retweets 771 likes
· Apr 29

annotated cross section of a typical USB cable.

7 replies 68 retweets 296 likes
· Apr 29

check out this cross section of an AC power cord. no, the other end is not plugged in.

8 replies 4 retweets 124 likes
· Apr 29

here's the cross section of the power cable. this is an older cord with outdated color codes. the filler also appears to be a natural material (possibly jute)

8 replies 7 retweets 64 likes
· Apr 30

flat phone cable, in cross section.

6 replies 10 retweets 159 likes
· Apr 30

cross section of an old-school VGA cable. i like the color coding. scale is 1mm/div.

6 replies 38 retweets 300 likes
· Apr 30

here's the annotated cross section of the VGA cable. each red, green, and blue signal gets its own little coaxial cable, as does the horizontal sync signal. vertical sync is low frequency and noise tolerant, so it's just a wire. same with the DDC signals (SDA, SCL, +5V, GND)

7 replies 36 retweets 166 likes
· Apr 30

cross section of a DVI-D single link cable. all that aluminum makes me think it's a cheap cable.

2 replies 11 retweets 113 likes
· Apr 30

and the DVI-D single link cable but with annotations.

2 replies 10 retweets 67 likes
· Apr 30

closeup of a single differential pair inside the DVI-D single link cable. the geometry has to be tightly controlled to maintain a constant impedance!

2 replies 7 retweets 54 likes
· May 1

for your inspection: this cross section of a USB-C connector. it's very complex!

11 replies 152 retweets 599 likes
· May 1

there really isn't enough room for all the annotations you'd need to fully describe this USB-C connector cross section. so here are the highlights.

2 replies 42 retweets 136 likes
· Apr 30

ever wonder what's inside your USB-C cable? here's a cross section of one! this one can handle 10Gbps.

25 replies 299 retweets 1,003 likes
· Apr 30

and this is what all the little wires and things are for. SBU stands for "SideBand Use"--DisplayPort alt mode uses them for I2C or CEC commands over a special encoded format. CC is the Configuration Channel and decides VBUS voltage and which end is source/sink.

7 replies 129 retweets 403 likes
· Apr 30

this cat6 cable is shielded and has a drain wire.

7 replies 14 retweets 122 likes
· Apr 30

and here's a cat6 patch cable! notice the plastic ➕ separator? it reduces crosstalk between pairs.

4 replies 22 retweets 157 likes
· Apr 30

and a super-thin cat5e patch cable.

2 replies 5 retweets 45 likes
· Apr 30

time to cut some network cables in half! here's a cat5e patch cable. 🐈 (thread)

8 replies 23 retweets 167 likes
· May 7

this is a cross section of a USB-C cable. it's different than the other USB-C cable that i sectioned earlier!

16 replies 78 retweets 412 likes
· May 7

annotated USB-C cable cross section. this cable got beat up a bit; one of the micro coax cables has gotten dented or deformed. you can see it's messed with the stranding a bit.

7 replies 51 retweets 166 likes
· May 10

it's Friday, so take a break from work and look at this: a cross section of a Micro-D connector!

4 replies 37 retweets 228 likes
· May 10

annotated version of the Micro-D connector cross section.

4 replies 15 retweets 83 likes

More Moments
Tana Mongeau clarifies comments about her wedding to Jake Paul being for 'fun and content'
Celebrity 2 hours ago
In the latest episode of her reality show, Mongeau said her wedding to fellow YouTuber Jake Paul was for "fun and content," prompting speculation that the ceremony was fabricated for publicity. The social media star has since addressed the speculation, saying her comments on the show were "pulled out of context."
1 Like
Joe Biden criticized for onstage greeting with Kamala Harris
Politics 4 hours ago
During night two of the second Democratic debates, Joe Biden shook hands with Kamala Harris and said: "Go easy on me, kid."
4 Likes
Michael Sheen explains why his name changed soon after his birth
Celebrity 3 hours ago
A lucky accident after Sheen's birth fulfilled the desire of his long-forgotten ancestors.
14 Likes
Clorox gets name-dropped after Kirsten Gillibrand throws an apparent jab at President Trump
Democratic primary debates 3 hours ago
When asked about the Green New Deal, Senator Gillibrand said that the first thing she’ll do as president is “to Clorox the Oval Office.”
3 Likes

The following Moment may contain sensitive content.

Previous
Next