Resistors

Resistors are passive devices that give you control over the currents and voltages that flow within a circuit. Electrical resistance describes how easy it is for electricity to flow through the circuit. By using a resistor, you can add resistance to the passage of an electric current, making it harder for electricity to flow through it.
 
Most resistors are small devices that have colored stripes around them to indicate the resistor’s tolerance and resistance. They are used in a wide range of applications, including:

• Digital electronics
• Measurement devices
• LED lights
• Air ventilation systems in cars
• Electric stoves
• Gas sensors

PUI Projections Unlimited stocks and distributes all types of electronic components, including various resistors for your application needs. Contact us today to learn more.

Types of Resistors

Some applications require a different amount of resistance or power, and some require a specific resistor material. For these reasons, there are a variety of resistors that are designed to meet the requirements of different applications.

Wire Wound Resistor

Wire wound resistors are created using an insulated, metallic wire with high resistivity that is wrapped around an insulating core of non-conductive material to provide resistance. This type of resistor is the oldest type still being produced, but they provide accuracy and excellent low resistance and high power properties.
 
Depending on the application for the wire wound resistor, a variety of materials and constructions can be used.  These types of resistors are primarily used for lower resistance values where a very thin wire can be used.  They are produced mainly using alloys, and can be created using:

• Copper alloy
• Silver Alloy
• Nickel Chromium Alloys
• Iron Chromium Alloys
• Iron Chromium Aluminum Alloys

Wire wound resistors are often found in circuit breakers or as fuses. They can also be used in large cooling water pumps, freezer units, and other applications where a high current condition may occur.

Power Resistors

Power resistors are compact resistors that are designed to withstand and dispel a lot of power, at least 5 Watt. They are efficient resistors that have been manufactured to dissipate the most power possible while still remaining small. They allow efficient cooling by using heat sinks, forced air, or liquid cooling.
 
There are many types of power resistors, including wire wound and SMD resistors, that are used for a variety of applications. They are primarily used for applications the require controlling large amounts of power. This includes applications like:

• Engine braking
• Load banks
• Neutral grounding resistors
• AC distribution systems

SMD Resistor

Surface Mounted Device (SMD) Resistors are small electrical are made to be used with surface mount technology. They are frequently used in circuit boards because they are small, but still fast, efficient, and cost-effective. Instead of wire leads, SMD resistors use small leads or pins that are then soldered onto the surface of the board.  
 
SMD resistors are available in a variety of sizes, shapes, and lead configurations to meet the application needs. They are made with a metal oxide film that determines the amount of resistance that it provides. SMD resistors are used for:

• Cell phones
• Televisions
• Commercial communications equipment
• Automatic assembly techniques
• Radio frequencies

Thru-Hole Resistor

Unlike surface mounted resistors, thru-hole resistors use wire leads that are attached to a breadboard, a prototyping board, or printed circuit board (PCB) through a hole and then soldered. They take up more space than a SMD resistor and are usually reserved for larger, bulkier components that need extra strength.  
 
Thru-hole resistors are typically made with a carbon-film or metal-film composition, but can also be wire wound or made of super-thin metallic foil. Because these resistors can be the more expensive option, they are often used for specific applications that require a higher temperature or power range.