Basic Electronics - Lesson 2 More About Resistors

More About Resistors

Resistors are More Fundamental and Commonly used of all the electronic components.
The Principal job of a Resistor within a electrical or Electronic circuit is to "Resist", regulate or to set the flow of electrons (Current) through them.

Typical Resistor

Standard Resistor symbol

Calculating the Resistance Value using Graphical Representation

like
B-B-R-O-Y-Great-Britain-Very-Good-Worker

We take Consideration from Narrowed Space End

if we have Resistor with Following colors - (Blue Black Brown and Gold)
Then the value of Resistor Would be -
Blue - 6 - First Digit
Black - 0 - Second Digit  which makes Value = 60
Brown - 1  - Multiplier value Which makes --> 60 * 10 = 600 Ohms

How To check Resistance

Finding the value of Resistor using Color Code is easy... But It is A cumbersome if  we have many Resistors With Different values and Going through entire Calculation Every time we need a Value.

So A device Called MULTIMETER is Useful for this purpose.

we can use it To Measure Voltage, Current, And Resistance.

A Multimeter has three Parts

1.Display

2.Selection Knob

3.Ports

Section Knob is used to Select the Parameter which user wanted to measure 

Measuring Resistance:

Points To Note :

Resistance is non-directional

You can only test resistance when the device you're testing is not powered

You can only test a resistor before it has been soldered/inserted into a circuit

If you have a ranging meter you'll need to keep track of what range you are in. Otherwise, you will get strange readings, like OL or similar, or you may think you're in KΩ when really you're in MΩ. 

Selecting the Range.

Please Note the Ohm symbol

Resistance In Series and Parallel

we can Calculate the Resistance of particular material Using formula

R = rho * l /A

where rho  -->  the resistivity of  the Material

l --> length of Material

A --> Cross Sectional Area

If we Connect Two Resistors in Series (End to End)  the Overall resistance is Increased

If we Connect Two Resistors in Parallel (Side by Side) then the Overall Resistance is Decreased

Resistors in series add together as R1 + R2 + R3 + ..... 

While resistors in parallel reduce by 1 / (1 / R1 + 1 / R2 + 1 / R3 + .....)

Measuring the Voltage

We need to Connect the Positive terminal of Battery to the Red wire and Negative terminal to The Black wire.. If we reverse the Polarity we are Gonna Have Negative Voltage.