Interview Question (your Sunday ruined part 2)

Jeroen Belleman

Are they allowed to use a calculator?

Does R330 mean 0.33 ohms?

I hate that sort of notation, like 2k47.

I keep having difficulty not using it in LTSpice.

R followed by a number is often used to designate values below 1. So, many interviewees will interpret the schematic as 0.8Ω in parallel with Rx. No way you can get 218 Ω between points A and B - unless you accept a negative resistance, in which case Rx is about -0.80295 Ω. :-)

Jest havin' fun. Or is that really what you want to mess their heads with?

Unless you believe in physics/SI notation.

So is R330 the reference designator?

Sorry, foreign notation. It's 330 ohms and 47 ohms.

Thought so. Personally, I sometimes use the European style of placing decimal values after the unit name, especially when space is limited as in a packed schematic. 4k7 takes up slightly less space than 4.7k *and* there's no chance of missing the decimal point. Likewise values like 6n8

LT Spice will happily accept 2k47 for 2470 ohms - you can even use

piglet

Maybe european decimal points slide off drawings and fall on the floor. Robust American decimal points and schematic connect dots don't do that.

How are things priced in a grocery store? Is the 'euros' symbol straddled by numbers on both sides?

The first thing a good intervuee should ask is "what the hell does R330 mean?"

The reason I try to avoid it outside locations where it's not questioned is because there's always someone who will ask what does

I wasn't aware that there was a difference between European and american decimal points.

Schematic connect dots are however much bigger, as you can see from LTSpice schematics. I'd estimate at least ten times bigger in area. Otherwise you may not have a connection at all.

The other legacy of unreliable dots (I suppose they used to fall off drawings 50 years ago) is people who refuse to make a clean 4-way connection with one dot. They insist on using two 3-ways, two dots with a clumsy offset.

no but € is behind the number not in front of it like $ ;)

Some people call them blobs and even with a blob I've had a four-way connection misinterpreted as a crossover.

It's harder to misunderstand, but no doubt some people can.

It means x is either between 1 and 46 or between 48 and 229.

It's a mistake. 330R would be common though, especially if you don't have an upper case omega.

I like it. I guess it's what you're used to.

There is a difference between English-speking ones and French-speaking ones: the French ones look like commas.