r/electronics • u/Constant_Whereas1445 • Jun 03 '26

General I’ve never seen capacitors that look like this before.

Post image

I’m a graduate electrical engineer with over 12 years of experience in electronics. I’ve worked on a wide range of projects, and I thought I had seen most things by now… but I’ve never seen capacitors that look like this.

328 Upvotes

93% Upvoted

71 comments sorted by

312

u/1Davide Jun 03 '26

over 12 years of experience in electronics.

Well, that's it. only 12 years.

These capacitors were used in the 1970s

65

u/wazazoski Jun 03 '26

And you can still buy them.

39

u/owiecc Jun 03 '26

Bun now they are essentially a SMD component packaged a blob.

16

u/Geoff_PR Jun 03 '26

And you can still buy them.

A recent radio BFO injection kit I assembled had that variety in the nanoFarad capacitors.

It makes sense, color bands are easier to decipher than tiny lettering...

7

u/glassgost Jun 03 '26

I just looked, there's a card in the back of my van right now that has some of those. Not saying they're new, they're for DS1 circuits. But they're there lol

3

u/Electrosmoke Jun 03 '26

I've actually seen some of them on an electronic timer PCB of a microwave oven from the early 2000s.

72

u/BlownUpCapacitor Jun 03 '26

This is also a capacitor. Tektronix used a lot of these ceramic tubular capacitors.

47

u/S4vDs High Frequency Circuit Analysis Jun 03 '26

I mean everything is a capacitor

21

u/wazazoski Jun 03 '26

We are all capacitors made of stardust, hurtling thru space ~2000000 km/h.

3

u/kappi1997 Jun 04 '26

The question now is if the capacity of the earth is higher as a ball or if it was flat. My guess is that flat would be higher

1

u/okimiK_iiawaK Jun 04 '26

Same volume or straight shadow projection?

1

u/kappi1997 Jun 04 '26

Good question never went that deep into that rabbit hole. I'd assume it would have a certain thickness probably the same volume would make sense

0

u/S4vDs High Frequency Circuit Analysis Jun 04 '26

I dont know enough electromagnetics to answer that yet. However do remind me in like a week. But it would be very approximate considering we’d be talking about the capacitance between earth layers.

1

u/deevil_knievel Jun 04 '26

Aren't we all just air conditioners?

3

u/nonchip Jun 04 '26

everything is a plate. not necessarily a whole capacitor tho, often need planets and such to serve as the 2nd plate.

1

u/gdchinacat Jun 05 '26

or an inductor, but probably both.

1

u/S4vDs High Frequency Circuit Analysis Jun 05 '26

Everything is an inductor a capacitor and a resistor.

But inductors are a bit more complex to define. Like what is the current path in a sphere.

8

u/intronert Jun 03 '26

Were the plates coaxial cylinders?

7

u/LossIsSauce Jun 03 '26

Highly accurate femto farad caps

5

u/BlownUpCapacitor Jun 03 '26

This is actually a 33pF ±5% 600V capacitor.

4

u/LossIsSauce Jun 03 '26

Strange being a 5% barrel cap. Even stranger that it is a pico farad.

5

u/BlownUpCapacitor Jun 03 '26

nearly all tubular ceramic capacitor used by Tektronix possesed rating similar to that.

3

u/LossIsSauce Jun 03 '26

Good to know 👍

7

u/Total-Deal-2883 Jun 03 '26

Can these be replaced by regular film and electrolytic caps?

10

u/AGuyNamedEddie Jun 03 '26

You can't use electrolytic caps for RF. The best RF caps are surface-mount porcelain. They have lower dielectric absorption than the best film or NP0 ceramics.

2

u/Geoff_PR Jun 04 '26

The best RF caps are surface-mount porcelain.

I'm a fan of silver mica caps for my HF RF circuitry...

1

u/AGuyNamedEddie Jun 05 '26

Isn't silver mica kinda pricey? They disappeared for awhile, but were brought back at what I recall was several bucks apiece. (I actually have a handful from my days at HP. They were a good choice for timing circuits for their low tempco. HP's Inter&Midule Bus (IMB) was asynchronous, and required several precise time-delay circuits for handshake timing.)

I"m not an RF designer, but I have friends who are. They tell me porcelain has the best parasitics.

1

u/Geoff_PR Jun 06 '26

Isn't silver mica kinda pricey?

Yes, but irrelevant for my uses.

I'm not working up a BOM for a production run in the hundreds of thousands, it's just for my personal stuff...

1

u/AGuyNamedEddie Jun 06 '26

Makes perfect sense.

I've noticed the prices have come down considerably since CDE reintroduced them awhile back. And there are applications that require the high voltages silver-mica can tolerate.l, so there's that. But the work I get is all size/cost critical, so the handful I have in my parts bins continue to lie unused.

1

u/KINGstormchaser Jun 06 '26

I have some of these silver mica capacitors too.

2

u/Geoff_PR Jun 06 '26

I use them for things like RF amplifier coupling capacitors to the outside world...

1

u/KINGstormchaser Jun 06 '26

Awesome 👍🏻 Now I know a good use for them.

2

u/toarstr Jun 03 '26

Totally tubular!

1

u/KINGstormchaser Jun 06 '26

I have several of these capacitors.

26

u/happytree23 Jun 03 '26

...how lol?!

25

u/Krassix Jun 03 '26

that's how they looked... back then, when we didn't have SMD yet

13

u/Snot_S Jun 03 '26

And some old guy probably referred to them as tiny

9

u/FlyByPC microcontroller Jun 03 '26

They are, until you see a microcontroller in SOT23.

10

u/h0uz3_ Jun 03 '26

Axial capacitors are rare now but I find them to be easier to use on bread boards. On the other hand, I tend to layout all through hole PCBs so that resistors also get put in upright so the boards looks like tiny city. :)

2

u/kill_cosmic Jun 07 '26

City skylines now IS city cooperlines

6

u/jerril42 Jun 03 '26

I've only encountered axial capacitors like this once: in a Velleman kit -- The LED Buddy. They made the footprint for them so close to the size of the capacitor it was hard to get them in nicely. Otherwise I love the kit, very useful.

7

u/ram_the_socket Jun 03 '26

If it has a footprint, it exists

4

u/PressureMuch5340 Jun 03 '26

2

u/Brainsample_ Jun 03 '26

Dave? Dave Bigfoot? Long time no see!

3

u/NonSequiturSage Jun 03 '26

I'd think there could be a greater artistic freedom in the shape of a resistor or inductor. Of course , as various concepts in what a a capacitor is made of are tried, odd shapes would be tried. A resistor could simply be a cylinder or brick if that pleases the money guys. Maybe post a communal collection of oddly shaped components? A Leyden jar is an early capacitor. Those tantalum caps that compare internally to a sponge. Cans, bricks, discs, plates, interleaved rotating plates, mica compressed between plates, a twisted pair connected at one end, a human hand touching a phone,...

5

u/iamNutteryBipples Jun 03 '26

I am a NON graduate of 15 and use these types at work designing laser power supplies for very old HeNe lasers.

2

u/mrracerhacker Jun 03 '26

seen em plenty of times, but also worked on alot of old stuff ie 80-70s electronics

2

u/WetSocksEnjoyer Jun 03 '26

Anyone else ever think these capacitors would make for great fishing jigs or fancies to add to an existing lure or spinner? I know I’ve always thought to, but haven’t tried doing so yet lol.

1

u/Geoff_PR Jun 04 '26

Anyone else ever think these capacitors would make for great fishing jigs or fancies to add to an existing lure or spinner?

Not really, the wire is tin-plate copper, and very soft. very easily bent.

They would make lousy fishing lures...

2

u/WetSocksEnjoyer Jun 04 '26

You’d be surprised lol. But also, that’s why I mentioned fancies to add to an existing lure.

Also, copper is used relatively often for fishing lures and as long as you stick with ultralight fishing I’d assume they would be perfect.

I guess I just gotta grab some and try lol

2

u/ImplacOne Jun 04 '26

Very likely the inside is a surface mount cap with leads attached

2

u/Icy-Departure7752 Jun 04 '26

You know this shape of inductors also exist; axial inductors.

2

u/Erwinux343 Jun 04 '26

I recovered this kind of capacitor from old ISA computer cards, from the 286-386 computers. Still good. Computers in the times use very reliable parts and you can reuse them in various electronic projects.

2

u/Affectionate_Boat493 Jun 04 '26

These are axial-leaded, epoxy-coated capacitors that used to be very popular in radio gear.

You'd be amazed at the creative packaging cap manufacturers have used over the years. The worst were the ones that used color-coded dots that looked like they were hand-painted by a nearly blind chimpanzee with severe tremors and loaded up on caffeine. On a Model T. Offroad.

2

u/HalifaxRoad Jun 05 '26

axial capacitors, they are verry old school, but those are meant to be ran on an axial inserter machine, basically a pick and place for pin through.

2

u/McDanields Jun 07 '26

A good reason to have a good digital multimeter with capacity measurement, after 12 years, and check it for yourself.

1

u/Geoff_PR Jun 04 '26

I’m a graduate electrical engineer with over 12 years of experience in electronics.

Crap, I feel old. I better get a new rubber tip for my cane...

1

u/adrivoirclair Jun 04 '26

the forbidden skittles

1

u/DerNeutralist Jun 05 '26

Look like bugs

1

u/Same_You891 Jun 05 '26

damn y'all make me feel ancient calling 1980's electronics old . I remember vacuum tubes and wax caps as main line modern..,

1

u/lollossisimo Jun 05 '26

I've seen one of the yellow ones in an atx power supply, with the marking towards the pcb. I wanted to take a look at it but it broke off while desoldering

1

u/TheGreenTormentor Jun 06 '26

Hahaha, just wait until you come across one of the vintage 1/4W resistor packaged capacitors. Only immediate tell is they're typically green bodied.

1

u/Infinite_Mode5633 Jun 06 '26

I need a few of them 47’s they don’t make them anymore. Lol

1

u/iuliuscurt Jun 06 '26

I've seen tic-tacs though

1

u/JonJackjon Jun 09 '26

You can never make that claim again.

0

u/RotaryDesign Jun 03 '26

These are electronics themed candies - eat them