555 Timer LED Flasher - What is Resistor ?
- Resistors are a specific, never-changing electrical resistance.
- Resistors are electronic components
- The resistor’s resistance restricts the flow of electrons through a circuit.
- Resistors are common elements of electrical networks and electronic circuits and are global in electronic equipment.
- Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated circuits.
- Variable resistors are called potentiometers
- There is a fixed value of resistance between two terminals
- The moving part of the potentiometer is called the wiper.
- Four band resistor colour code
- 1st band provides the first digit of the code
- 2nd band provides the second digit of the code
- 3rd band is the multiplier
- 4th band indicates the tolerance value
Resistor colour code calculation
- The first band red has a value of 2
- The second band purple has a value of 7
- The third band has a multiplier of x 10
- The last band indicates a tolerance value of +/-5%
- Resistance value is 270Ω +/-5%
- The behaviour of an ideal resistor is dictated by the relationship specified by Ohm's law:
- Ohm's law states that the voltage (V) across a resistor is proportional to the current (I), where the constant of proportionality is the resistance (R).
Series and parallel resistors
- The total resistance of resistors connected in series is the sum of their individual resistance values.
- The total resistance of resistors connected in parallel is the reciprocal of the sum of the reciprocals of the individual resistors.