Hello all firdt time poster and im sure il be posting more
Going back to basics im re- teaching myself from my old gcse books from ten year ago lol.

I got the 4 band resistors down to a T but i recently bought a pack of leds that specified what resistors i weanted for them, i asked for 12 volt ones and what i got in the post with leds were blue resistors with 5 bands on them, so i looked up color codes for 5 bands and the diagrams all say that there should be 1 band on the lip of the resistor the other 4 in side the middle before the last lip..Well mine have 3 in middle and 1 on each lip so how do i tell which end to use? i tried to input into a calculator both ways for one sequence beinghbrown violet black black yellow but it dont look right? brown and yellow on the ends? one result was a 1 Mohm for an led seems high?

some clarification and help would be most apreciated.

Also Whats difrence between E12 and E3 series resistors 1/4wat 5% ?
they both have resistors in there series which are same in both? i dont get that. thanks in advance

 

i didnt know the answer to these questions so i googled and from what i can work out, the difference between e12 and other e series is the manafacturing tolerance percentage.
E12 is a 10% tolerance band series of resistors.
e12 is so called because there are 12 values spaced exponentially across a 10 times resistance change. eg between 1k and 10k there are 12 values of resistor in the e12 series. The actual value of any resistor could therefore be within 10%.
See link about standard eia resistor values
Resistor Values E6 E12 E24 E48 E96 E192

apparantly 5 bands are used both for more precise resistors where a 3rd value is required e.g 2.34k but more likely i would assume on your resistor as an indication of the temperature coefficeint. The link below has a table with temp coefficent colours on.

Resistor Color Chart

Get yourself a multimeter and you can measure the resitance of your resistors to see what they are.

I don't know how in depth a gcse textbook goes but i too am trying to learn electronics and i'm using a textbook called 'the art of electronics' by horowitz and hill. I highly recommend it.

***my 100th post***

 

firstly gratz on 100th post
second thanks for answers i think i got the answers i needed
E12 being 10% and reason i was confused is that the pack of resistorsi bought E3 had 16 values with gold band 5% tollerance and the e12 pack i got was also gold band 5% both packagaing had 1/4 watt 5% labelled next to the E3 E12 , just in E12 there was more resistor values in it. but judging by the link you gave me E3 is being discontinued so maybe E 12 is a combination or old and new? i dunno as for the 5 band problem i get what ya saying it makes sense just maybe theresistors i got were poorly printed.

Thanks for replys though

Just realised also E12 like you say is 10% tollerance so therefore should have final silver band? packageing says they are e12 5% so does that mean that the whole Series E12 or what ever can have difrent tollerances so again why the difrent series LOL bah...

 

i guess what they have done is made a pack of resistors to the nominal E12 values ie 1k, 1.2k, 1.5k, 1.8k, 2.2k, 2.7k, 3.3k, 3.9k, 4.7k, 5.6k, 8.2k, 10k but instead of having them at 10% manafacture tolerance they are 5% in this case.
If you had bought a E24 series resistor bag (5% tolerance) you would have twice as many resistors so i guess they do this for people who dont need all the value resistors but need more accuracy than 10%.

 

but that then means that E12 does not mean resistors with 10% tolelrance and E3 is 5% ie the series being linked to the amount of tollerance they have! so still what is the difrence lol.. Actually have look on maplin site lol

Maplin > resistor pack

Top 2 packs i bought any ways it matters not as long as they work right? lol only reason i wanted to know is to make sure when i start building circuits i dont use inproper electronic compnents.