• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Newb Resistor questions

Status
Not open for further replies.

Darkpriestt

New Member
Hello all firdt time poster and im sure il be posting more:D
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
 

confounded

New Member
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***
 
Last edited:

Darkpriestt

New Member
firstly gratz on 100th post:D
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...
 
Last edited:

confounded

New Member
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%.
 

Darkpriestt

New Member
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.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top