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SMD Resistor Coding Explained

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assembly resistors are the most widely

used type of resistors among the

different resistors and these type of

resistors are used in the production of

various electronic equipments like

televisions smartphone and even

high-tech R&D equipments now if you

closely observe the printed circuit

boards of these electronic equipments

then you will find that the small code

is written on top of this surface mount

resistors so basically this code defines

the value of these resistors so now in

this video let us find out how we can

decode this code and from this how we

can find the value of this surface mount

resistors now usually the three types of

coding schemes are used for this surface

mount resistors so let us see them one

by one

so the first type of coding scheme is

the three-digit coding scheme so in this

scheme the 3 digits are used to define

the value of the resistors now out of

the three digits the first two digits

defines the two most significant digits

of the resistor value while the third

digit defines the multiplying factor for

the resistor value so now let us take

some examples for this three digit

coding scheme so for example if the code

that is written on this assembly

resistor is 223 it means that the value

that is represented by this resistor is

equal to 22 into 10 to the power 3 that

is equal to 22 kilo ohm so here the last

digit is 3 it means that the value would

be multiplied by the 10 to the power 3

and hence the value is equal to 22 kilo

similarly for the core of 430 the value

of the resistor would be equal to 43

into 10 to the power 0 that is equal to

43 ohm and likewise if the code that is

written on the resistor is 3 0 5 it

means that the value of the resistor

would be equal to 30 into 10 to the

power 5 that is equal to 3 macao now

sometimes in these three digit coding

schemes the later R is used to define

the position of the decimal point so for

example

the code that is written on the register

is who are two it means that the value

of the resistor is equal to two point

two ohm and likewise for the code of r39

the value of the register would be 0.39

ohm so basically this later R is used to

define the position of the decimal point

so in this way by using this three digit

code we can find the resistor value so

now similarly let us see the four digit

coding scheme so this type of coding

scheme is also very similar to the 3d

coding scheme so in this a four digit

coding scheme out of the four digits the

first three digits defines the three

most significant digits of the register

value while the last digit defines the

multiplying factor for this resistor

value so let us take some examples for

this four digit coding scheme so for

example if the core that is written on

the surface mount of this term is 1 0 0

1 it means that the value of the

register would be 100 into 10 to the

power 1 that is equal to 1 kilo and

similarly for the case of Phi 1 0 3 the

value of the resistor would be Phi 1 0

into 10 to the power 3 that is equal to

Phi 1 0 kilo so in this way by using

this four digit coding scheme we can

find the resistor value now in this four

digit coding scheme also the later R is

used to define the position of the

decimal point so for example if the code

that is written on the resistor is two

or seven zero it means that the value of

the resistor would be equal to two point

seven ohm and likewise if the code that

is written on the resistor is 0 or 2 4

then the value of the resistor would be

point 2 4 ohm now many times in the PCB

assembling this assembly jumpers are

also used now theoretically the

resistance of this assembly jumpers used

to be a zero so whenever you find this

type of force that is written on the

surface mount resistors it means that

the value of this resistor is equal to

zero now apart from these three and four

digit coding schemes for the high

precision resistors this third type of

coding scheme is also used so this type

of coding scheme is used for the

resistors

which has a 1% of Tolerance so in this

game three characters are used to define

the register value now out of the three

characters the first two characters used

to be a number and last character used

to be a later so these first two digits

defines the three most significant

digits of the register value while the

last later is to define the multiplying

factor for the register value so here is

a table which defines the different

codes for the last letter and the

corresponding multiplying factor and

here is the another table which defines

the first two digits of the code and the

corresponding value that is represented

by this first two digits so using these

two tables we can find the value of the

resistor for this type of coding scheme

so now let's say we have one register

and the code that is written on this

resistor is 3 6 C now if you look this

code the first two digits of this code

is 36 in the corresponding value that is

represented by that code is 232 and the

last letter of these code is C so the

multiplying factor for this register

would be equal to 100 so from this we

can say that the value of the register

would be equal to 232 multiplied by 100

that is equal to 23 point two kilo so in

this way by using these two tables we

can find the value of the register so

let us take few more examples so that it

will get clear to you so let us say we

have one more resistor and the code that

is written on the register is 0 5 Y now

from the first two digits of this code

we can say that the value that is

represented by this code is equal to 1 1

0 and here the last letter is Y so the

corresponding multiplying factor is

equal to point zero 1 so from these two

tables we can say that the value of the

register will be equal to 1 1 0

multiplied by point 0 1 that is equal to

1 point 1 ohm so similarly let us take

one more example so if the code that is

written on the resistor is 48 D then we

can say that the value of the resistor

will be equal to still is 0 9 multiplied

by thousand so the value of the resistor

would be equal to 3 0 9 hello so in this

way

by using these two tables we can find

the value of the resistor for this type

of coding scheme so I hope in this short

tutorial you understood how to find the

value of the surface mount resistors

from the code that is written on these

resistors so if you have any question or

Sedition do let me know in the comment

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