Resistors-Through Hole

Part Number	Description / PDF	Quantity
PWR221T-30-5600F J.W. Miller / Bourns	RES 560 OHM 30W 1% TO220	0
PWR221T-30-50R0F J.W. Miller / Bourns	RES 50 OHM 30W 1% TO220	890
PWR220T-20-1R00F J.W. Miller / Bourns	RES 1 OHM 20W 1% TO220	0
PWR221T-30-R025J J.W. Miller / Bourns	RES 0.025 OHM 30W 5% TO220-2	0
PWR221T-30-R200F J.W. Miller / Bourns	RES 0.2 OHM 30W 1% TO220	0
PWR220T-20-1R50F J.W. Miller / Bourns	RES 1.5 OHM 20W 1% TO220	138
PWR221T-30-25R0J J.W. Miller / Bourns	RES 25 OHM 30W 5% TO220	0
WS5M22R0J J.W. Miller / Bourns	RES 22 OHM 5W 5% AXIAL	0
PWR220T-35-20R0F J.W. Miller / Bourns	RES 20 OHM 35W 1% TO220	0
PWR221T-30-R300J J.W. Miller / Bourns	RES 0.3 OHM 30W 5% TO220-2	0
PWR220T-20-3R00F J.W. Miller / Bourns	RES 3 OHM 20W 1% TO220	682
PWR220T-20-8R20J J.W. Miller / Bourns	RES 8.2 OHM 20W 5% TO220	0
PWR220T-20-3R00J J.W. Miller / Bourns	RES 3 OHM 20W 5% TO220	0
PWR221T-30-R250F J.W. Miller / Bourns	RES 0.25 OHM 30W 1% TO220	245
PWR221T-30-1000F J.W. Miller / Bourns	RES 100 OHM 30W 1% TO220	620
PWR221T-30-10R0J J.W. Miller / Bourns	RES 10 OHM 30W 5% TO220	231
WS5A1001J J.W. Miller / Bourns	RES 1K OHM 5W 5% AXIAL	0
PWR221T-30-7R50F J.W. Miller / Bourns	RES 7.5 OHM 30W 1% TO220	174
PWR221T-30-75R0F J.W. Miller / Bourns	RES 75 OHM 30W 1% TO220	0
PWR220T-35-2R20J J.W. Miller / Bourns	RES 2.2 OHM 35W 5% TO220	33

Resistors-Through Hole

1. Overview

Through Hole Resistors (THRs) are axial-leaded electronic components designed to limit current flow and divide voltages in circuits. They are mounted by inserting leads into printed circuit board (PCB) holes and soldering on the reverse side. As foundational passive components, THRs maintain circuit stability and precision across industries. Despite the rise of surface-mount devices, THRs remain critical for high-power applications and prototyping due to their durability and ease of manual handling.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Carbon Film Resistors	Low noise, stable performance, cost-effective	General-purpose electronics, consumer devices
Metal Film Resistors	High precision ( 0.1% tolerance), low temperature coefficient	Medical instruments, test equipment
Wirewound Resistors	High power handling (up to 50W), accurate resistance values	Power supplies, industrial machinery
Ceramic Composition Resistors	High surge current resistance	Power line filters, lighting ballasts
Fusible Resistors	Acts as both resistor and fuse	Overcurrent protection in power circuits

3. Structure and Composition

Typical THRs feature:

Lead Wires: Tin-plated copper or silver alloys for solderability
Resistive Element: Carbon/metal film or wound nichrome wire
Insulating Body: Ceramic or glass-epoxy coating
Marking: Color bands (EIA-438B standard) or printed text

Advanced designs incorporate flame-retardant coatings and precision laser-trimmed elements for 0.01% tolerance.

4. Key Technical Specifications

Parameter	Typical Range	Importance
Resistance Value	1 to 100M	Determines current/voltage control
Power Rating	1/8W to 50W	Defines maximum power dissipation
Tolerance	0.01% to 5%	Indicates resistance accuracy
Temperature Coefficient	5ppm/ C to 300ppm/ C	Measures stability over temperature
Voltage Rating	200V to 1000V	Prevents dielectric breakdown

5. Application Fields

Consumer Electronics: Power management in TVs, audio equipment
Industrial Control: Motor speed controllers, PLC systems
Telecommunications: Signal conditioning in base stations
Automotive: Engine control units, LED lighting systems
Medical Devices: Precision measurement in diagnostic equipment

Case Study: Metal film resistors in ECG machines provide 0.1% tolerance for accurate heart signal detection.

6. Leading Manufacturers and Products

Manufacturer	Key Products
Vishay Precision Group	Y1485 series ( 0.005% tolerance wirewound)
Yageo Corporation	MF-RC series (metal film, 1/4W to 2W)
Panasonic Electronic Components	EVR series (ceramic composition, 250V rating)
Bourns Inc.	CR2800 series (fusible resistors)

7. Selection Guidelines

Key considerations:

Determine required power dissipation (select 2x calculated wattage)
Match tolerance to application needs (e.g., 0.1% for audio amplifiers)
Verify temperature coefficient for operating environment
Consider voltage ratings for high-voltage circuits
Check RoHS compliance for environmental regulations

Example: Selecting a 10 , 10W wirewound resistor for a 24V DC motor driver circuit.

8. Industry Trends

Current development directions:

Miniaturization while maintaining power ratings (e.g., 5W resistors in 1210 package)
Advancements in laser trimming for sub-ppm level precision
Adoption of eco-friendly materials meeting REACH/SVHC standards
Integration with smart manufacturing systems for automated placement
Development of high-temperature resistant models (up to 300 C operating)

Market growth projections indicate a CAGR of 4.2% through 2030, driven by automotive electronics demand.