Real-Life Applications of Resistors in Everyday Devices
Resistance is the speed breaker to the heavy traffic of current through the closed circuit. It has various applications and we can easily find at least one use of resistance in a circuit.
So, what happens is, when electrons start flowing through the circuit under the push, i.e., the potential difference, they collide with ions, and because of this electricity flow rate or the current decreases, and in one word, we denote it as resistance. Also, the use of resistor generates heat in the circuit.
On this page, we will understand what is the use of resistance and the application of resistance.
How Does Resistance Works?
You spend your schooldays talking about conductors and insulators. You know what a conductor is, it is something that allows electricity to flow through it easily. The insulator is just the opposite – it is something that does not let the current flow through it easily.
The difficulty to the current flow properties is a direct result of resistance – conductors like copper have a low resistance to the electric current flow, whereas insulators resist the flow of electric current to a large degree, i.e., have a large resistance.
If we zoom into a wire to the atomic scale, we see that the wire is made of tiny atoms, just like in the image below:
(Image to be added soon)
When electrons flow through the wire, some of these pass easily through the gaps in the wire, while some of them hit an atom and bounce, sometimes electrons collide with each other; this makes the flow of electrons somewhat non-uniform and impeded (slow current flow rate) – this is resistance.
This also means that resistance depends on the type and properties of the material itself since the interaction of the electrons with the atoms depends on the size and packing of the atoms.
Resistance and Temperature
Considering a circuit model, when we heat the wire, we are supplying energy to the wire. This energy gets absorbed by the atoms which then start vibrating. These vibrations make it more difficult for the electrons to get through.
Now, we will write uses of resistors with their applications:
Application of Resistance
Now, we will write uses of resistors in points and then explain these one-by-one:
Circuit functions
LEDs and transistor
Dividing voltage
Heating
Frequency and timing
What is the Use of Resistance?
Following are the uses of resistors:
Use of Resistor in Circuit Functions
There are different types of resistors that work according to the usage range. In this, we can set the resistance value by using a kind of feature called a knob.
Any changes in a resistance value affect the flow of current inside the circuit.
The use of resistor in circuit functions are:
In controlling the speed of a motor,
The pitch of a musical tone, and
The loudness of an amplifier.
Use of Resistor in LEDs and Transistor
An overflow of the current through LEDs and transistors can be very dangerous, so an electric component called the resistance is employed to overcome this danger.
Also, LEDs and transistors are very sensitive to electric current. So, the use of resistors in the circuit will help the LEDs and transistors, and other various types of semiconductors to function in the required current range ideal for them.
Use of Resistor For Heating
Because of the collision of ions inside the material, some obstruction generates is the resistance, and this, in turn, produces a lot of heat when conducting current,
We find the use of a resistor in a heater, toaster, microwave, electric stove, and many more heating appliances.
In a light bulb, the metal filament (made of tungsten) glows white-hot due to the very high temperature produced from the resistance (slow electricity flow rate) when electricity is passed through it.
Use of Resistance to Function in Particular Timing and at Specific Frequency
Various circuits use a resistor connected to a capacitor to access the timing source. Devices like light flashers, electronic sirens, blinking lights and many other circuits rely on this feature.
The devices mentioned above are used in airplanes and tall towers to work as a collision avoidance measurement. Here, these devices work on the phenomenon of filling up current to a certain time and then discharge light. The resistor decides whether how much current has to be passed at a particular time.
If the resistance in the circuit increases, the time for discharging current in the circuit also increases.
A capacitor holds an electric charge like a bucket holds the water and takes a specified time to fill with current, and the resistance ascertains how fast the capacitor fills.
Use of Resistance for Diving Voltage
Dividing the voltage (the potential difference) works when some components are required to operate in a much lesser voltage than the supplied input voltage. Connecting the resistors in a series will aid in dropping the voltage across each resistor equally, thus, helping the appliances smoothly which works in those conditions.
FAQs on Practical Uses of Resistor in Physics
1. What is a resistor and what is its primary function in an electrical circuit?
A resistor is a passive electrical component with a specific electrical resistance. Its primary function is to impede the flow of electric current. This control over the current is fundamental in electronics for protecting components, dividing voltages, and setting time constants in circuits.
2. What are the main applications of resistors in everyday electronic devices?
Resistors are used in nearly every electronic device. Their key applications include:
- Current Limiting: Protecting sensitive components like LEDs from excessive current by placing a resistor in series with them.
- Voltage Dividers: Using two or more resistors to split a voltage source into a smaller, required voltage for another part of the circuit.
- Heating Elements: In devices like toasters and electric heaters, resistors are designed to dissipate a large amount of heat as current passes through them.
- Signal Control: In audio equipment, variable resistors (potentiometers) are used to control volume by adjusting the resistance in the signal path.
3. What are the most common types of resistors found in electronics?
The most common types of resistors include:
- Fixed Resistors: These have a constant resistance value. Carbon film and metal film resistors are common examples, identifiable by their colour bands.
- Variable Resistors (Potentiometers): These allow the resistance to be adjusted manually. They are often used as control knobs for volume, brightness, or tuning.
- Light Dependent Resistors (LDRs): Their resistance changes based on the intensity of light falling on them, making them useful in automatic streetlights and light sensors.
- Thermistors: Their resistance varies significantly with temperature, making them ideal for use in digital thermometers and temperature-activated switches.
4. Why is a resistor essential for protecting a component like an LED?
An LED (Light Emitting Diode) is designed to operate within a very narrow range of voltage and current. If connected directly to a power source like a battery, it will draw too much current, causing it to burn out almost instantly. A resistor is placed in series with the LED to limit the current to a safe level. It essentially 'resists' the excess flow, ensuring the LED receives only the current it needs to light up without being damaged, thereby extending its lifespan.
5. What is the fundamental difference between 'resistance' and a 'resistor'?
This is a key distinction in electronics. Resistance is an electrical property that measures the opposition to the flow of current. It is an abstract quantity measured in Ohms (Ω). A resistor, on the other hand, is the physical component or device specifically designed to possess and exhibit a certain amount of resistance in a circuit. In simple terms, a resistor is the object, while resistance is the characteristic it possesses.
6. How does a variable resistor, or potentiometer, function to control volume in an audio device?
A potentiometer is a three-terminal resistor with a rotating or sliding contact that forms an adjustable voltage divider. In a volume control circuit, the full audio signal is applied across the two outer terminals. The middle terminal, which is connected to the amplifier, can be moved along the resistive element. When the knob is turned, it changes the position of the middle terminal, tapping off a different voltage level from the audio signal. This adjusts the signal's amplitude before it reaches the amplifier, thereby increasing or decreasing the volume you hear.
7. How are resistors used to create a voltage divider, and why is this circuit configuration so important?
A voltage divider is a simple circuit made by connecting two or more resistors in series. The input voltage is applied across the entire series, and the output voltage is taken from the connection point between two resistors. According to Ohm's law, the voltage drop across each resistor is proportional to its resistance. This allows you to create a lower, stable output voltage from a higher input voltage. This configuration is extremely important because it allows a single power source to supply different voltage levels required by various components within the same circuit, which is a fundamental requirement in complex electronic designs.
