types of resistor

What is resistor?

The resistor is an electronics component, it use for current limit and it do voltage down.

The resistor is a small component but it’s highly required in any circuit, because any electronics component such as Transistor, ICs, LEDs, need different voltages, for this we use a resistor in any circuit.

Suppose: - We have one 1.5v LED and we want glow it by 6v or 12v battery, so we require a resistor which will control to voltage and LED will glow smoothly without any harm.

Resistance is the opposite of flow of free electrons, means resistor will create some restrict in current flowing.

You know that any wire has some resistance which restrict to current and voltage, for this we get voltage losses, but normal used wires has very low resistance, but some material has high resistance, like nichrome, tungsten etc.

Construction of resistor

We use high resistance material for make a resistor; we give many turns to higher resistance wire, and it make like cylinder. Turns numbers is depended on resistance value because we require different values resistor, because any component needs different voltage and current in any circuit.

Resistor values take in ohms and denoted by (Ω) or (R).
The resistors used always in series it cannot use in parallel, if use it in parallel then resistor may be break or burnt.

Types of resistor

We have commonly three types of resistor

1- Fixed Resistor

2- Variable Resistor

3- Dependent Resistor

1- FIXED Resistor 

Resistor The fixed resistor has always fixed rating, means is has always one value like 1 ohm, 5 ohm 100 ohm etc. its values we can't adjust by self, if we require change values then we change resistor.

The fixed resistor also has 3 types

  • Carbon Film Resistor
  • Metal Film Resistor
  • Fusible Resistor 

 

1-    Carbon film resistor

This type resistor inside a thin carbon film wounded, when its body is ceramic type and it shape like cylinder.

2-    Metal film resistor

This types Resistor body is ceramic but it has inside metal wire or layer, which wounded in round shape, this resistor shape also like a cylinder.

Both resistors such as Carbon film and Metal film Resistor is very similar, the metal film resistor has only inside material difference, metal film and carbon film.

3-    Fusible Resistor

The fusible resistor looks like a resistor but its work is same like a fuse, it protect against overload to any circuit, when circuit will over load then it be fuse.

      2- VARIABLE Resistor


potentiometer The variable resistor has different values, it ohms value we can adjust by self, means if we have a 10 kilo ohm variable resistor, so it we can change into 10 ohm 100 ohm, 1k, 5k, etc.

The variable resistor inside a carbon type paper which has different resistance at any point

 


                                                    


We have typically 2 types of variable resistor

  • Potentiometer Variable Resistor
  • Trimmer variable Resistor

1-    Potentiometer variable resistor

This types resistor is big in size, and it we can easily adjust by hand, this types resistor mostly used in ceiling fan dimmer, DC voltage power supplies, speakers for volume control, and etc.

     2-    Trimmer variable resistor

This types resistor is very small in size, it we can't adjust by hand, it we adjust by screw driver, it fixed in circuit which needs one time resistance setting, such as stabilizer, UPS, battery charger, etc.   

    3- DEPENDENT Resistor 

LDR 

The Dependent resistor is totally depended on environment, this resistor is some similar to variable resistor because its resistance can change, but not by hand or screw driver, its resistance change by environment signals, such as by Heat, Light, and also it is depended on current and voltage changing.

We have also 3 types of dependent Resistor

  • Light Dependent Resistor
  • Heat Dependent Resistor
  • Current/voltage dependent Resistor

1-    Light Dependent Resistor

This types resistor known as LDR and photo resistor, it is very small in the size, but is very useful resistor, it we take as a sensor, because it changing resistance by light sense, means its resistance will has different in Lighting and darkness.

The LDR used in mostly road's night lamp, which will on and off automatically in night and morning.

2-    Heat Dependent Resistor

This types resistor also known by thermistor resistor, its looks like a capacitor, its resistance will change with temperature changing. it can sense temperature and change own resistance, for this it used in automatic room heater, Water gyser, and air conditioners, also it used in temperature meter.

3-    Current/voltage dependent Resistor

This types resistor looks like to fixed resistor, but its resistance will change by voltage and current changing, it can protect to any circuit with high or low voltage and current, it can easily protect by voltage fluctuating in any circuit, for this it used in power supplies, because power supplies face to voltage fluctuating.