The Comprehensive Guide to 250 Ohm Resistor

Among the various resistance values, the 250 ohm resistor is a commonly use value, especially in applications where need to achieve specific current levels or voltage drops. Resistors are integral components in electronic circuits, use to control the flow of current by offering resistance. Here is catalog in this blog post:

1. What is a 250 Ohm Resistor?

2. 250 Ohm Resistor Color Code And Identification

3. Key Specifications of a 250 Ohm Resistors

4. 250 Ohm Resistor In 4-20mA Current Loops

5. The Role of 250 Ohm Shunt Resistor

6. Selecting The Right Resistor 250 Ohm: A Practical Guide

7. 250 Ohms Load Resistor

8. 250 Ohm Resistor Price

9. Frequently Asked Questions (FAQs)

1. What is a 250 Ohm Resistor?

A 250-ohm is a passive electronic component that resists the flow of electric current. Specifically design to offer 250 ohms of resistance, meaning it restricts the current passing through it in an electrical circuit. This resistance value is use in controlling the amount of current flowing through different components of the circuit, preventing overcurrent that can damage sensitive parts. Come in different types and power ratings, which allow them to meet specific electrical requirements. A 250-ohm available in both through-hole and surface-mount designs, allowing for versatile uses across kinds of electronics.

Can use 250Ω in a wide variety of applications, including:

Industrial and Process Control: In systems using 4-20mA current loops, use a 250 Ω is to convert current into a voltage for easy measurement. LED Circuits: In controlling the current through LEDs, ensuring they operate within their rated current. Sensor Circuits: In voltage dividers for sensor signal conditioning.

In summary, a 250-ohms is a versatile, commonly use component that helps regulate current, protect circuits, and enable precise control in many electronic systems.

2. 250 Ohm Resistor Color Code And Identification

To identify a 250Ω, we can refer to the colour coding, which varies depending on whether it’s a 4-band, 5-band, or 6-band resistor.

4-Band Color Code:

First-Band: Red (2), second-Band: Green (5), third-Band: Brown (Multiplier: ×10), fourth-Band: Gold (Tolerance: ±5%), result = 2 5 ×10 = 250 ohms ±5%. Red - Green - Brown - Gold.

5-Band Resistor Color Code:

1^st-Band (Red): 2. 2^nd-Band (Green): 5. 3^rd-Band (Black): 0. 4^th-Band (Black): Multiplies by x1 (no change). 5^th-Band (Brown): Indicates a tolerance of ±1%. Resistance Values: The final value is 250 ohms with ±1% tolerance. Red - Green - Black - Black - Brown.

6-Band Resistor Color Code:

A 6-band colour codes provides more precise information than a typical 4-band or 5-band. The 6^th-band includes additional information of the temperature coefficient.

1^st-Band (Red): 2. 2^nd-Band (Green): 5. 3^rd-Band (Black): 0. 4^th-Band (Black - Multiplier): Multiplies by x1. 5^th-Band (Gold - Tolerance): Tolerance is ±5%. 6^th-Band (Red - Temperature Coefficient): Indicates a ±50 ppm/°C temperature coefficient.

The final resistance value is 250-ohms with ±5% tolerance and a temperature coefficient of ±50 ppm/°C.

3. Key Specifications of a 250 Ohm Resistors

Power Rating: Determine how much power it can safely dissipate without being damaged. Common wattage for a 250Ω include:

1. 250 Ohm Resistor 1/4 Watt

A low-power rating suitable for general-purpose circuits where the circuit doesn’t need to dissipate much energy. Commonly in standard electronic applications such as signal processing and low-power voltage dividers. Applications in voltage dividers, current-limiting circuits (e.g., LED circuits) and analog signal conditioning.

2. 250 Ohm Resistor 1 Watt

This medium-power can handle more power dissipation compared to the 1/4W. Use in circuits where expect moderate current, such as in audio equipment or small power supplies.

Applications power supplies, audio equipment and signal filtering.

3. 250 Ohm 5 Watt Resistor

A high-power component suitable for industrial applications or circuits that involve higher currents. Build to handle more heat and are typically larger in size, such as wirewound type. Applications high-power voltage regulators, power distribution circuits, motor control and heavy-duty.

4. 250 Ohm 10 Watt Resistor

A high-power often use in industrial, automotive, or other high-load applications. Have excellent heat dissipation capabilities and design to endure continuous high current. Applications in power supplies for industrial machinery, high-power resistive load, motor and battery discharge circuits.

Tolerances depending on the application requirements. Defines the accuracy of the resistor's value. Common tolerances for a 250-ohm are: ±0.005%, ±0.01%, ±0.02%, ±0.05%, ±0.1%, ±0.25%, ±0.5%, ±1%, ±2%, ±5%, ±10%. High-precision resistors tend to have lower tolerance values (e.g., ±0.005%). 

250-ohm come in various package types, including:

SMD (Surface Mount Device): Sizes 0201, 0402, 0603, 0805, 1206, 1210, 1812, 2010, 2512.

Through Hole: Available as Axial, Radial, and TO-220 packages.

Construction Types of 250-Ohms:

1. Metal Film: Made by depositing a thin layer of metal (usually nichrome) onto a ceramic substrate. The resistance determine by the length, width, and thickness of the metal layer. Offer high accuracy, better than carbon film type, low noise, and stable temperature coefficients. They also provide better tolerance, usually ±1%, ±0.5%, or better. Use in precision applications where require accuracy and stability, such as audio equipment, measurement devices, and signal processing circuits.

2. Metal Oxide Film: Made by depositing a layer of metal oxide (such as tin oxide) onto a ceramic base. Provides better performance at higher temperatures compared to metal film types. Have high-temperature stability, making them able to operate at higher temperatures than metal film type. They also have a high power dissipation capacity and are more durable in harsh environments. Typically use in industrial applications requiring high-temperature stability, such as power supplies, high-power resistors, and power management systems.

3. Thick Film: Manufacture by applying a thick layer of resistive paste onto a ceramic substrate, followed by a sintering process. The thick layer gives the resistor its characteristic size. Cost-effective compared to metal and wirewound types. They can use for SMD (Surface-Mount Device) applications and handle moderate power levels. Common in low to medium-power applications, and often in consumer electronics, automotive, and telecommunications.

4. Thin Film: Made by depositing a thin layer of resistive material (like nickel-chromium or tantalum) onto a ceramic substrate, allowing for precise control over the resistance value. Offer high precision and accuracy, better than thick film and metal film types. They have a low temperature coefficient, meaning minimal change in resistance with temperature variations, and are highly reliable with low noise. Use in high-precision circuits such as instrumentation, measurement systems, and applications requiring low tolerances, such as analog-to-digital converters (ADCs) and oscillators.

5. Wirewound: Made by winding a thin wire of a resistive material (such as nichrome or tungsten) around a core (usually ceramic or metal). The resistance control by adjusting the length and thickness of the wire. Wirewound types have a high power handling capacity. They are accurate, stable, and can handle high-energy dissipation without overheating. Commonly use in power applications such as power supplies, motor control circuits, and high-current circuits, including current shunt resistors for precise current measurements.

Each type has distinct advantages suited to different applications, so the choice of resistor construction depends on factors such as power handling, tolerance, temperature stability, and size requirements.

4. 250 Ohm Resistor In 4-20mA Current Loops

A 250-ohm is commonly use in 4~20mA current-loop circuits, which are standard in industrial automation, process control, and sensor systems. Use the resistor to convert the current signal into a voltage that can easily measure by a device such as a controller or an analog-to-digital converter (ADC). Here’s how a 250R functions within this context:

In a 4-20mA current loop, the current is proportional to the measured value, such as pressure, temperature, or flow. The range of 4mA to 20mA typically corresponds to the sensor's minimum and maximum values. Place 250-ohm in series with the current loop. Its role is to convert the current signal into a voltage that can read by a voltage measurement device such as a programmable logic controller (PLC) or data acquisition system. The current flowing through the resistor creates a voltage drop across it, which is directly proportional to the current in the loop.

Voltage Calculation: The voltage across the 250-ohms will vary depending on the current in the loop. At the lower end of the current range (4mA), the voltage will be low, and at the (20mA), the voltage will be higher. This change in voltage can measure by the monitoring equipment, allowing for accurate reading of the process variable.

Specifically choose the 250-ohm because it provides a voltage range that is compatible with most PLC analog inputs, which typically accept a 1V to 5V signal. This makes it ideal for most industrial control systems.

Applications: In industries such as oil and gas, chemical processing, and manufacturing, where needs to transmit sensor data over long distances without degradation. Use the 250Ω in these systems to ensure interpret the analog signal accurately. Also commonly in process control and automated systems where the resistor helps ensure reliable voltage conversion.

Advantages of Using a 250-Ω:

A low-cost, effective solution for converting current signals into voltage. The circuits helps maintain signal integrity, especially over long distances, without interference. Also compatible with most control and monitoring equipment, offering a simple solution for voltage conversion in industrial systems.

5. The Role of 250 Ohm Shunt Resistor

A shunt resistor is a precise low-resistance component use to measure current by developing a small voltage drop proportional to the current passing through it. The 250-ohms shunt circuit is often use in current measurement applications, providing a simple yet effective way to measure current in various circuits, especially in power supplies, battery monitoring, and power distribution systems.

Place the 250-ohm shunt in series with the circuit, allowing current to flow through it. As current flows through the resistor, create a voltage drops across it. This voltage drop is directly proportional to the current flowing through the circuit, according to Ohm's Law. In many industrial and electronic applications, measuring the voltage-drop across the 250-ohms shunt circuit enables the calculation of the current without directly measure the high current itself. Instead, only the voltage drop across the resistor needs to measure, making this approach both cost-effective and efficient.

Can use in battery management systems (BMS) to monitor the current being drawn from or supplied to a battery. The voltage drop across the shunt resistors use to calculate the charge or discharge current, providing data on the state of the battery. Also used in power distribution systems to monitor and control current flow. Can use to ensure that the circuit is operating within safe current limits and can trigger protective measures if the current exceeds a predefined threshold. In systems involving motors or large loads, a 250-ohm shunt circuit can use to monitor the current consumption, ensuring that motors or other electrical equipment operate within their rated current limits.

Provide accurate current measurements, as the voltage drop across it is directly proportional to the current. Shunt resistors are also low-cost components compared to other current measurement methods, such as Hall-effect sensors or current transformers, making them a cost-effective solution for current monitoring. Additionally, shunt resistors are easy to integrate into existing circuits, offering simplicity and versatility. Can use in both high-current and low-current applications, making it suitable for a variety of systems.

In conclusion, the 250-ohm shunt resistor is a necessary component in many measurement and control systems. It enables precise current measurements by converting current into a proportional voltage drop, which can easily monitor and interpret. Its simplicity, accuracy, and cost-effectiveness make it an ideal solution for applications such as current loop systems, battery management, power monitoring, and motor control.

6. Selecting The Right Resistor 250 Ohm: A Practical Guide

When selecting a 250-ohm resistor, it's necessary to consider various factors to ensure it fits the specific needs of your application.   

1. Packaging Type:

The packaging type depends on the size constraints, the method of mounting, and the power requirements of the application.

SMD (Surface-Mount Device) Packaging Types:

Common sizes : 0201 , 0402 , 0603 , 0805 , 1206 , 1210 , 1812 , 2010 , 2512.

SMD-2: A smaller, specialized surface-mount package typically use for precision components, often in low-power circuits.

TO-263: A larger SMD package with a heat sink tab, typically use for higher-power components such as voltage regulators, power transistors, and power resistors that require extra heat dissipation.

Through-Hole Packaging Types:

Axial-resistors, the leads exit from opposite ends, resembling a cylindrical shape. This package commonly use in applications where needs to insert into holes on a PCB (Printed Circuit Board). Often use in power supplies, high-energy applications, and legacy circuits.

Radial: Have leads that come out in the same direction, making it more compact compared to axial types. These also insert into PCB holes. Commonly use in power electronics, automotive circuits, and general-purpose applications.

TO-220: Larger and has a heat sink tab, making it suitable for high-power resistors or devices that require heat dissipation. This package commonly use for high-power applications, power transistors, voltage regulators, and power-management systems.

2. Temperature Coefficient:

Define how much the resistance will change with variations in temperature. For precision applications, choosing a resistor with a low TC ensures the resistances remains stable across a wide temperature range. A 250-ohm resistor with a low TC (e.g., ±50 ppm/°C or lower) prefer for applications where temperature stability is important, such as high-precision measurement systems. Precision applications require a TC as low as ±25 ppm/°C for minimal drift. General-purpose applications tolerate higher values such as ±100 ppm/°C.

3. Environmental Factors:

Condition where the component will use can affect its performance. Consider factors:

Humidity: If use in high-humidity environments, look for moisture-resistant or sealed-resistors to prevent degradation. Corrosive Environments: For applications in harsh conditions (e.g., chemicals or high salt content), select with protective coatings or corrosion-resistant materials (such as metal oxide film type). Temperature Extremes: Automotive and aerospace applications require with high temperature tolerance (e.g., -55°C to 150°C).

4. Application-Specific Requirements:

Different applications have unique requirements that should influence the choice of types:

Power Circuits: If use in high-power applications (e.g., power-supplies, motor control), you will need a higher wattage rating and a larger package type (e.g., TO-220 or 2512).

Signal Processing: For low-power signal processing circuits, a small SMD resistor with high precision and low tolerance is ideal, such as an 0805 or 0603 size.

Precision Instruments: For applications requiring high accuracy (e.g., calibration, measurement), select a precision type with a tighter tolerance and lower temperature coefficient.

5. Power Rating:

Define how much power can dissipate without overheating or being damaged. For a 250-ohm resistor, the wattage rating can vary based on the packaging type and material:

Low Power: 1/4 watt or 1/2 watt (e.g., 0603, 0805) typically use for signal processing or low-power circuits.

Medium Power: For higher powering dissipation, prefer 1-watt or 2-watt (e.g., 1206, 1210).

High Power : For high-power circuits (e.g., power-supplies or motor control), 5-watt or 10-watt(e.g., 2512, TO-220) are better choices to prevent overheating.

6. Tolerance:

Indicates how much the actual resistance can vary from the nominal value, can vary depending on the application:

General-Purpose: ±5% or ±1% is sufficient for many everyday electronic applications. Precision Applications: For high-accuracy circuits (e.g., calibration, measurement systems), need a tighter range such as ±0.5% or ±0.1% to ensure minimal variation in resistance. High-Precision Circuits: In applications requiring extremely tight control, typically select with tolerances as low as ±0.05% or ±0.02% .

By carefully considering these factors, you can ensure that the 250-ohm will meet the performance, reliability, and durability requirements of your specific application.

7. 250 Ohms Load Resistor

Used in various electrical and electronic applications to simulate a load, dissipate power, or control current within a circuit. Particularly useful when testing or calibrating power supplies, amplifiers, or other electronic devices that require a known resistance.

Applications of 250-Ohm Loads Resistors:

1. Power Supply Testing: Used in load testing of power supplies to simulate a real-world load. This allows engineers to verify the output voltage and current capabilities of the power supply under different conditions.

2. Amplifier Testing: In audio amplifiers, use a load resistor to simulate speakers, allowing engineers to check the performance of the amplifier and ensure it can drive a load effectively.

3. Current Simulation: Used in current loops or to simulate current in a circuit. When use with 4-20mA current-loop, the 250R acts as a load and helps simulate the system’s expected operating conditions, facilitating calibration and performance verification.

4. Prototyping and Circuit Design: Use in prototype circuits to simulate real-world conditions, ensuring that designs can handle expected power and current levels before finalizing the circuit.

5. Voltage Divider Circuits: Can use in voltage divider circuits to step down voltages to desired levels in signal conditioning, sensing, or measurement applications.

6. LED Circuits: Use to limit current to an LED or other components, preventing overcurrent conditions and ensuring the proper operation of the circuit.

In conclusion, a 250-ohms load resistor is a versatile component use in various testing and simulation applications. Careful selection will ensure that it performs effectively in your specific application.

8. 250 Ohm Resistor Price

The prices varies depending on the type, tolerance, and power rating. Standard carbon film types may cost just a few cents, while precision metal film or higher power type can cost more, typically ranging from $0.010 to $0.50 per unit.

Bulk Purchases: You can usually get a significant discount when purchasing in bulk.

Shipping Costs: Consider shipping costs, especially when buying small quantities, as they can impact the overall price.

9. Frequently Asked Questions (FAQs)

1. What is a 250 ohm resistor used for?

A 250-ohms is commonly use in electronic circuits for various purposes, such as limiting current, voltage regulation, and signal processing. Often in current-limiting applications like LED circuits or voltage dividers to adjust signal levels. It also utilize in 4-20mA current loops for converting current signals to measurable voltages in industrial and process control systems. Helps maintain appropriate current levels, ensuring that other components, such as sensors or microcontrollers, not damage by excessive current.

2. What color is a 250 ohm resistor?

The colour code with a 4-band type is Red - Green - Brown - Gold. In this system, the first two color bands represent the digits (Red = 2, Green = 5), giving "25." The third-band (Brown) acts as the multiplier (×10), so the total value is 250 ohms. The fourth-band (Gold) indicates the tolerance, which typically represents a ±5%. In the 5-band or 6-band systems, precision and tolerance values would be more refined.

3. Is 250 ohms too high?

Whether 250-ohm is too high depends on the circuit’s requirements. For many applications, such as current-limiting in low-power circuits or voltage dividers, 250 Ω is a perfectly reasonable value. However, in high-current or high-power circuits, this resistance value might consider too low, as it could lead to excessive current flow. Conversely, for voltage-regulation tasks or signal conditioning, 250Ω is a common, effective choice. The resistance should match the voltage and current specifications for the specific component or system it is using with.

4. What is the voltage drop across a 250 ohm resistor?

Depends on the current flowing through it. According to Ohm's Law, the voltage drop is directly proportional to both the current and the resistance. For example, in a typical 4-20mA current loop, the voltage drop across a 250Ω will range from 1V 4mA to 5V 20mA. This means the 250-Ω helps to convert the current signal into a measurable voltage, which often use in industrial control systems and sensors. The voltage drop ensures proper signal transmission without overloading the circuit components.

5. What is the difference between HART and 4-20mA?

HART (Highway Addressable Remote Transducer) is a communication protocol use in industrial automation for two-way data transmission. It uses 4-20mA current loops as the physical medium but superimposes digital signals on the analog current to allow for more detailed information exchange. The 4-20mA current-loop is a standard method for transmitting analog signals in process control systems. While 4-20mA only conveys continuous values, HART allows for additional diagnostics, configuration, and control data to transmit over the same loop, making it more versatile than standard analog current loops.

6. Why 250 ohm resistor used in hart communicator?

Because it converts the 4-20mA current loop signal into a readable voltage for controllers and field devices. In a HART system, the current loop carries both the analog process signal and superimposed digital signals. The 250-ohms acts as a voltage drop element, converting the current into a measurable voltage. For example, at 4mA, the voltage is 1V, and 20mA, it is 5V. This voltage signal is then processed by control systems to monitor and control devices remotely.

7. How do I measure the resistance of a 250 ohm resistor?

Use a digital multimeter and set to measure resistance (Ω). Connect the multimeter’s probes to both ends of the 250Ω, ensuring good contact. The display will show the resistance value. If the resisyance is not within the expected range (i.e., close to 250 ohms), it may be faulty or out of tolerance. Be sure to measure the resistances when it not connect to any active circuit, as current flow can affect the reading.

8. Where can I purchase 250 ohm resistors?

You can purchase 250Ω-resistors from Orwintech Electronics, either directly through our website or by contacting sales department. We typically offer a wide range of resistors, including carbon film, metal film, SMD, and high-power types.

You can browse our product catalog, select the specific types and quantity you need, and make a purchase. We offering these resistors in smaller quantities for personal or DIY projects and also available in bulk purchasing options to buy at a competitive pricing per unit. If you need bulk purchases or specific technical support, Orwintech's customer service team would be a helpful point of contact.  

In conclusion, the 250-ohm resistor is a necessary component in both general-purpose and specialized applications. Understanding its specifications, role in circuits, and how to choose the right type will help you incorporate it effectively into your designs. Whether you’re using it in a 4-20mA current loop or as part of a precision circuit, the 250-ohm resistor remains a cornerstone of electronic design.

Read More:

1. 200 Ohm Resistor - Complete Guide Color Code & More

2. Complete Guide to the 220 Ohm Resistor

3. 1 Ohm Resistor: A Complete Guide