What are these new numbers on resistors?

[gary350]

What does 4R2 mean?

And others?

 

[Nigel Goodwin]

It's not 'new', it's decades old, it means 4.2 ohms.

 

[cowboybob]

4.2 OHMs

Nigel, how come the "Insert math" button options doesn't have the OHM symbol? It shows in the Tab, but not among the options:

I see "small" Omega, \[ \omega \], but not capital Omega.

 

[dknguyen]

4.2 OHMs

Nigel, how come the "Insert math" button options doesn't have the OHM symbol? It shows in the Tab, but not among the options:
View attachment 114982

There is an arrow on the bottom right for more symbols.

\[ \Omega \]

 

[cowboybob]

... There is an arrow on the bottom right for more symbols.

Where?

 

[dknguyen]

4.2 OHMs

Nigel, how come the "Insert math" button options doesn't have the OHM symbol? It shows in the Tab, but not among the options:
View attachment 114982

It's right in your screenshot. Very very bottom right.

 

[cowboybob]

Ok. I see it now (pretty small...) \[ \Omega \]

Is there a way to do a better job of placing the symbol?

Middle of the page kinda sucks...

 

[dknguyen]

\( \Omega \)\[ \Omega \]

Pick inline in the math editor instead of block.

 

[gophert]

Blah

 

[audioguru]

I think blind people who cannot see a decimal point or blind printers that could not print a decimal point wrote the silly 4R2 instead of 4.2 Ohms.
They did capacitors the same: 4n7 instead of 4.7nF. They never wrote frequencies silly like that. 55Hz5 instead of 55.5Hz?
Henries?? Sizes?? Weights??

 

[Nigel Goodwin]

I think blind people who cannot see a decimal point or blind printers that could not print a decimal point wrote the silly 4R2 instead of 4.2 Ohms.
They did capacitors the same: 4n7 instead of 4.7nF. They never wrote frequencies silly like that. 55Hz5 instead of 55.5Hz?

They don't generally need to print frequencies on small components - it's obviously a VERY good idea, as it's much clearer than a decimal point that might, or might not, be clearly visible.

 

[cowboybob]

\( \Omega \)
Thanks, dk...

 

[dknguyen]

Well, specks of dirt and grim can look like decimel points. Decimel points can also wear off or just not be printed properly to begin with. I've seen more than one component with imperfect printing.

 

[JonSea]

Audioguru's usual snarky response isn't entirely accurate. There's a new scheme of marking E96 resistors to accommodate increased resolution.

 

[atferrari]

Audioguru's usual snarky response isn't entirely accurate. There's a new scheme of marking E96 resistors to accommodate increased resolution.

View attachment 114990

So, now, we need to carry the above table to know what the significant figures are.
Not a perfect solution.

 

[JonSea]

Yeah, I was looking at a board I had assembled checking resistor values in a section that wasn't working right. "What the heck is that? It's definitely not the resistor I specified!" Oops.

 

[Nigel Goodwin]

Well I always use 1% resistors now, and it's a nightmare figuring out which end to read the colour code from

Gold and Silver tolerance bands were so much easier, and of course one stripe less.

 

[gophert]

Well I always use 1% resistors now, and it's a nightmare figuring out which end to read the colour code from

Gold and Silver tolerance bands were so much easier, and of course one stripe less.

Then buy Vishay resistors. They gave up on color bands and just print the numeric value on the part.

 

[KeepItSimpleStupid]

They don't generally need to print frequencies on small components - it's obviously a VERY good idea, as it's much clearer than a decimal point that might, or might not, be clearly visible.

I had an AM/FM/SW Blaupunkt car radio that was laid out in wavelength, 1950's style radio was in cps (cycles per second.

With real blueprints, it was easy to loose a decimal point. I remember blueprints for an 1980;s ISI scanning electron microscope. then audio equipment done in the 80's too, but I have some never published stuff.

JonSea. Thanks for the heads up.

 

[schmitt trigger]

Early document copying techniques, among them blueprints, would significantly loose resolution after the second generation copy.

Even though I studied electronics with the 0.1uF system, I thought that the 0u1F was actually very clever, and use it sometimes.

And if you want to go real old nomeclature, does anyone remember micromicrofarads? uuF = pF?

Also, if I recall correctly, Gigahertz radio frequencies were expressed by its wavelength in centimeters or millimeters.