resistor question?

[subplay]

Hi I have a schematic im rebuilding. on the diagram, the resisitors feeding the leds are 330 ohm. But in there there is one resistore the says 3.3m

What is this one can you please help, and would anyone be able to give me a link to where to buy in the uk..

Thanks again all

 

[subplay]

Whats a 3.3m resistor?

Hi all im making a circuit of a schematic, I need 10 330ohm resistors, but 1 x 3.3m

Can anyone clarify what that is? and is there a link where I could pick up one from...

or is the 3.3m another way of saying 330 ohms?

Thanks

 

[davenn]

hi
is it really shown as 3.3m or is it really shown as 3.3M or 3M3 ?

3.3M or 3M3 = 3.3 MegaOhms ( they don't make 3.3 milliOhm resistors as far as I'm aware)

Upper and lower case lettering is extremely important to get correct in electronics and physics in general

and Mr Ohm would prefer you capitalise his surname

lower case m = milli (1/1000th) upper case M = million

Dave

 

[(*steve*)]

That is either 3.3M (3,300,000 Ohms) or 3.3m (0.0033 Ohms).

Can you check whether it's "m" or "M", and even better, show us the schematic.

A 3.3m resistor would typically be in series with a high current load (say between 30 and 200A) or as a shunt for a current meter (effectively the same).

A 3.3M resistor is a very high value and would be (perhaps) in a timing circuit, or other places with very low currents.

 

[(*steve*)]

Subplay, can you see why we get annoyed by people starting multiple threads for exactly the same topic?

 

[duke37]

There are several places to get components in the UK. I get my bits from R.F Potts of Derby. Most big towns have a Maplins. RS components, Farnell, Cricklewood, Bowood are alternatives to get them by post.

 

[KrisBlueNZ]

Ohm should not be spelled with an initial capital unless you are specifically talking about Mr. Georg Simon Ohm, or his Law. It's correct to say that a resistor value is 10 ohms (without the capital O).

When a unit is written as a single letter, the capital is used; for example, 10 µF (microfarads). There are exceptions: seconds should always use the lower-case letter: ps, ns, µs, ms, s, to distinguish them from siemens, the unit of conductance, which uses the upper-case letter. Times written with units of "µS" and "mS" are often seen, but are wrong.

The SI units for resistance should be written milliohm, ohm, kilohm (not kiloohm or kilo-ohm) and megohm (not megaohm or mega-ohm).

Other units that are named after people follow the same pattern:

picofarad, nanofarad, microfarad, millifarad, farad (named after Michael Faraday);

microvolt, millivolt, volt, kilovolt, megavolt (named after Alessandro Volta);

nanoamp, microamp, milliamp, amp (named after Ampere);

nanohenry, microhenry, millihenry, henry (named after Joseph Henry) (There doesn't seem to be a consensus on whether the plurals should be written microhenrys, etc, or microhenries, etc.)

 

[davenn]

I could agree except where there is a prefix else its a capital

Henry etc

SI units

Base units: *Ampere ·*Candela ·*Kelvin ·*Kilogram ·*Metre ·*Mole ·*Second

Derived units: *Becquerel ·*Coulomb ·*Degree Celsius ·*Farad ·*Gray ·*Henry ·*Hertz ·*Joule ·*Katal ·*Lumen ·*Lux ·*Newton ·*Ohm ·*Pascal ·*Radian ·*Siemens ·*Sievert ·*Steradian ·*Tesla ·*Volt ·*Watt ·*Weber

Dave

 

[Miguel Lopez]

There are exceptions: seconds should always use the lower-case letter: ps, ns, µs, ms, s,

Units are only represented with capital letters symbols when they are derived from a person's name.

second, meter, mol, candela, radian....etc should always be represented as symbols using non-capital letters.

The only exception that I now remember is litre, which can be represented with a capital "L" to diferentiate it from the symbol for length "l" or from the number "1"

 

[KrisBlueNZ]

Thanks Miguel for the clarification.