Resistor Basics

what is resistance

The electrical resistance of an electrical element measures its opposition to the passage of an electric current

how should the power rating of resistors be chosen

it should be about twice the power consumption needed

what is a resistor

A resistor is a two-terminal passive electronic component which implements electrical resistances a circuit element

what is one Mnemonic for remembering the sequence of the resistor color code

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how does a resistor function

When a voltage V is applied across the terminals of a resistor, a current I will flow through the resistor in direct proportion to that voltage

since a resistor acts as a current limiter what is one way it can be seen as in a plumbing analogy

a flow constrictor

in order to measure a resistor of less than 1 ohm with accuracy what does it require

a four terminal connection

if the average power dissipated by a resistor is more than its power rating what happens

damage to the resistor may occur permanently altering its resistance and causing erratic behavior or circuit failure

if a capacitor is a storage device how can adding a resistor add a time delay

since a capacitor could be seen as a bucket and a resistor as flow constrictor, constricting more flow would increase the time it takes to fill the bucket

what does the power rating indicate

the amount of power a resistor can safely dissipate

what is the temperature coefficient

the change in resistance as the device warms

what is the unit of resistance

the ohm

what does the tolerance rating indicate

the precision of the resistor given as a percentage. Resistors within tolerance will only vary their resistance by the amount of tolerance

what is the function of a resistor

to limit current

how much power does most resistors in circuits dissipate

usually no more than 1/4 and sometimes 1/2 watt

how do you test resistors

with an ohmmeter