Types of Resistors

If you’ve ever wondered about the backbone of electronic circuits, consider this: resistors make up about 70% of all components in a typical circuit.

As you look into the world of resistors, you’ll find a diverse range of types, each with its own unique characteristics and applications. From fixed resistors providing stable resistance values to specialized resistors designed for specific functions, the realm of resistors is vast and intriguing.

Understanding these various types can significantly enhance your grasp of electronics and their practical use.

Fixed Resistors

What are the characteristics that make fixed resistors the most common type in electronic circuits?

Fixed resistors are prevalent due to their constant resistance value, which remains unchanged under normal operating conditions. This stability ensures consistent performance in various electronic applications. 

Additionally, fixed resistors are manufactured using different materials, allowing for customization based on specific circuit requirements. The influence of these materials on properties like tolerance, cost, and noise makes fixed resistors versatile components in circuit design.

Furthermore, fixed resistors are available in axial and SMD packages, catering to different types of circuit layouts and space constraints. Their compact size and ease of integration make them ideal for densely populated circuit boards. 

The simplicity of fixed resistors, with their predetermined resistance values, simplifies circuit design and troubleshooting processes.

Variable Resistors

Variable resistors, also known as potentiometers or rheostats, offer adjustable resistance values through mechanical movement. These components allow you to fine-tune the resistance in a circuit to achieve the desired output.

Here are four reasons why variable resistors are essential in electronics:

1. Precision Control 

With variable resistors, you have the power to make precise adjustments to resistance, enabling you to fine-tune voltage levels or control currents with accuracy.

2. Flexible Circuit Design 

The adjustable nature of variable resistors offers flexibility in circuit design, allowing you to adapt and optimize electronic devices for specific requirements.

3. Troubleshooting Aid

By tweaking the resistance using a potentiometer, you can troubleshoot circuits by isolating the source of issues related to resistance levels.

4. Experimental Exploration 

Variable resistors open up a world of experimentation, where you can explore the impact of resistance on different circuit parameters, fostering a deeper understanding of electronics.


Moving from the realm of variable resistors, Thermistors offer a unique functionality with their significant resistance changes in response to temperature fluctuations. These devices come in two main types: Negative Temperature Coefficient (NTC) thermistors, which decrease resistance as temperature rises, and Positive Temperature Coefficient (PTC) thermistors, which increase resistance with temperature. 

Due to this property, thermistors are commonly employed as temperature sensors or thermal protection devices in various applications.

One of the key advantages of thermistors is their high sensitivity to temperature changes, making them ideal for precise temperature measurement and control. When integrated into circuits, thermistors can accurately detect variations in temperature, triggering necessary adjustments or protective actions. 

Additionally, their small size and low cost make them a practical choice for temperature-sensitive systems.


Varistors, known for their nonlinear resistance characteristics dependent on voltage, play a crucial role in electronic circuits, especially for over-voltage protection. They’re essential components that rapidly decrease resistance above a threshold voltage, safeguarding your devices from voltage spikes and surges.

Here are four reasons why varistors are indispensable in electronic circuits:

1. Protecting Your Electronics

Varistors act as a shield, absorbing excess voltage and diverting it away from sensitive components, ensuring the longevity of your devices.

2. Ensuring Reliability 

By promptly responding to voltage variations, varistors help maintain the stability and reliability of your electronic equipment, preventing potential damage.

3. Peace of Mind 

With varistors in place, you can have peace of mind knowing that your devices are safeguarded against unexpected voltage fluctuations that could otherwise harm them.

4. Cost-Effective Protection 

Varistors offer cost-effective over-voltage protection, potentially saving you from expensive repairs or replacements due to electrical surges.

Specialized Resistors

After exploring the essential role varistors play in protecting electronic circuits from over-voltage situations, let’s now shift our focus to specialized resistors that offer unique functionalities.

One such resistor is the Light Dependent Resistor (LDR), which decreases in resistance with increasing light intensity. LDRs are commonly used in applications that require the identification of light or dark situations, such as automatically switching on street lights in the evening.

Another specialized resistor is the Magneto-resistor, designed to detect and measure magnetic fields. The resistance of a Magneto-resistor changes with the strength and direction of the magnetic field it’s exposed to.

These unique resistors serve specific purposes in various electronic circuits, providing tailored solutions to specific sensing and control needs. Understanding the characteristics and applications of specialized resistors can enhance your ability to design and troubleshoot electronic systems effectively.

Light Dependent Resistors

Light Dependent Resistors, also known as LDRs, exhibit a decrease in resistance as the intensity of light they’re exposed to increases. These components are fascinating due to their unique behavior in response to light.

Here are four intriguing facts about Light Dependent Resistors:

1. Sensitive Souls 

LDRs are incredibly sensitive to light changes, making them ideal for light detection applications.

2. Darkness Warriors

In darkness, LDRs offer high resistance, acting as guardians against unwanted light-triggered actions.

3. Light Lovers 

When exposed to light, LDRs rapidly decrease their resistance, embracing the illuminating power with open arms.

4. Twilight Dwellers 

LDRs thrive in the twilight, smoothly transitioning their resistance as the day shifts from light to dark and back again.

Understanding the dynamic nature of Light Dependent Resistors can shed light on their vital role in various light-sensing circuits and devices.


Magneto-resistors detect and measure magnetic fields by exhibiting changes in resistance based on the strength and direction of the magnetic field. This unique property makes them valuable in applications requiring magnetic field sensing. 

By utilizing the magneto-resistive effect, these resistors can provide precise measurements of magnetic fields, offering a practical solution for various industries.

One significant advantage of magneto-resistors is their sensitivity to magnetic fields, allowing for detailed detection even in low-intensity fields. This sensitivity enables them to be used in compasses, position sensors, and magnetic field imaging applications. 

Additionally, their ability to operate over a wide range of temperatures makes them versatile in different environments.

When considering magneto-resistors for your project, ensure you understand the specific requirements of the magnetic field measurements needed. By selecting the appropriate magneto-resistor type and configuration, you can achieve accurate and reliable results in your magnetic field detection applications.

NTC Thermistors

Considering the sensitivity and precision required in magnetic field detection applications, exploring NTC Thermistors introduces a valuable element in temperature-dependent resistance technology. NTC Thermistors exhibit a decrease in resistance as temperature rises, making them ideal for applications like temperature sensing and compensation.

Here are four key aspects that make NTC Thermistors stand out:

1. High Sensitivity 

NTC Thermistors offer high sensitivity to small changes in temperature, providing accurate and responsive temperature measurements.

2. Wide Operating Range 

With a wide operating temperature range, NTC Thermistors can function effectively in various environments and applications.

3. Stability 

These thermistors demonstrate stable and reliable performance over time, ensuring consistent temperature readings.

4. Cost-Effectiveness

NTC Thermistors are a cost-effective solution for temperature sensing applications, offering excellent performance at a reasonable price point.

PTC Thermistors

PTC Thermistors, also known as Positive Temperature Coefficient thermistors, exhibit an increase in resistance as temperature rises. This unique characteristic sets them apart from NTC thermistors, making PTC thermistors valuable components in various applications.

When exposed to temperature changes, PTC thermistors limit the current in a circuit by increasing their resistance, serving as self-regulating heating elements or overcurrent protection devices. Due to their positive temperature coefficient, PTC thermistors are commonly used in applications where temperature stabilization or protection against overheating is crucial.

Their ability to automatically limit current flow as temperatures rise offers a simple and effective solution to prevent circuit damage or ensure consistent operating conditions. By understanding the behavior of PTC thermistors, you can leverage their properties to enhance the reliability and safety of electronic systems in diverse settings.

MOV Varistors

With a distinct behavior from PTC thermistors, MOV Varistors provide nonlinear resistance characteristics based on voltage levels, making them crucial components in circuit protection against over-voltage situations. MOV varistors exhibit a rapid drop in resistance above a certain threshold voltage, effectively shunting excess voltage away from sensitive components and preventing damage to the circuit.

Here are four key points to consider about MOV Varistors:

1. MOV varistors are like silent guardians in your circuit, ready to spring into action and protect your electronics from harmful voltage spikes.

2. Their nonlinear resistance response adds a dynamic element to your circuit, ensuring that only excessive voltages are blocked while allowing normal operation to continue.

3. Think of MOV varistors as the first line of defense against electrical surges, standing firm to shield your devices from potential harm.

4. By incorporating MOV varistors in your designs, you can rest easy knowing that your circuits have a robust defense mechanism against over-voltage events.


You have now explored the diverse world of resistors, from fixed resistors with constant values to variable resistors allowing adjustment.

Thermistors change resistance with temperature, varistors provide over-voltage protection, and specialized resistors react to light and magnetic fields.

Understanding these various types of resistors is crucial for designing and implementing electronic circuits effectively.

Keep exploring and experimenting with resistors to enhance your knowledge and skills in the field of electronics.