The PD ultra-precision TO-220 through-hole power resistor series from Alpha Electronics offers a power rating of up to 8W on a heat sink or 1.5W in free air (at 25°C) over a wide resistance range of 0.1Ω to 10kΩ. By utilising Alpha’s Bulk Metal® foil resistor technology, they are able to offer low temperature coefficients down to ±2.5 ppm/°C between the resistance range 5Ω and 10kΩ as well as tight tolerances down to ±0.02% between 25Ω and 10kΩ.
Ultra-precision through-hole power resistor
Each resistor is available in any resistance between 0.1Ω and 10kΩ
TO-220 through-hole package
Power rating of 8W on a heat sink or 1.5W in free air at +25°C
Tight tolerances as low as ±0.02% available between 25Ω and 10kΩ
Tight TCR available of ±2.5 ppm/°C between 5Ω and 10kΩ
Maximum working voltage of 250V
Maximum working current of 4A
Maximum rated operating temperature +25°C
Temperature range from -55°C up to +155°C
The PD ultra-precision power resistor series exhibits excellent high frequency characteristics thanks to Alpha’s Bulk Metal® foil resistor technology, making them suitable for the most demanding precision applications. Their standard TO-220 package is commonly used for power semiconductor devices making them ideal for new power designs.
Pin pitch for the Alpha PD series is 5.08 ±0.5mm.
The below table gives a summary of the specifications and options available for the Alpha PD series:
* Symbols parenthesized are for part number composition
✝ Resistance figures are the values obtained by measuring the leads at point 5.08 ±0.6mm away from the root
** For heat sinking, an aluminium chassis in 152.4 (L) x 101.6 (W) x 50.8 (H) x 1.0mm (T) shall be used
Alpha PD Series Datasheet
Alpha Electronics PD ultra-precision TO-220 through-hole power resistor series datasheet
Supporting Product Information
Alpha Manufacturing and Product Information
Alpha Electronics manufacturing process, adjustment of resistance value construction, and temperature characteristics of resistance information
We are pleased to provide you with a range of videos, please see below for the latest content available:
VIDEOS
Resistor Stability Put to the Test (Demo Video)
In this video, our host Richard Zuratt puts the stability of the three major resistor technologies — foil, thin, and thick film — to the test. Each resistor type is subjected to an overload pulse and its change in resistance value is recorded. Due to the homogeneous nature of the VPG Bulk Metal® Foil resistor, it is the only of the three to experience no change from the high power pulse. This demonstrated performance makes foil resistors the technology of choice for critical applications where long-term stability and survivability are paramount.
Advantages of Using Bulk Metal® Foil Resistors in High-Humidity Environments
All resistors that are based on nichrome, which is a category that includes both thin film devices and Bulk Metal Foil resistors, are susceptible to electro-chemical corrosion or etching when placed in a high humidity environment and powered with a very low wattage. But since the nichrome element of a Bulk Metal Foil resistor is hundreds of times thicker than the element in a thin film device with the same value, it will last much longer under these conditions. This video shows the actual etching process and survival times for thin film and foil nichrome resistive elements as they are tested in 100% humidity conditions.
Comparison Testing of Chip Resistor Technologies Under High Vibration
Surface-mount resistors suffer physical stresses when exposed to high vibration or thermally unstable environments. Failure modes commonly occur in welds, solder joints, connectors, and terminations, ultimately resulting in circuit failure. In this demonstration, vibration-table-mounted boards are subjected to ±2° deflection 25 times per second and monitored for any ΔR > 0.1%. All the chip resistors failed in 2 to 12 minutes (8K to 16K cycles). But the Alpha MPP molded Bulk Metal® Z-Foil resistor with flexible terminations experienced over a million cycles with no change in resistance.
VIDEOS
Resistor Stability Put to the Test (Demo Video
In this video, our host Richard Zuratt puts the stability of the three major resistor technologies — foil, thin, and thick film — to the test. Each resistor type is subjected to an overload pulse and its change in resistance value is recorded. Due to the homogeneous nature of the VPG Bulk Metal® Foil resistor, it is the only of the three to experience no change from the high power pulse. This demonstrated performance makes foil resistors the technology of choice for critical applications where long-term stability and survivability are paramount.
Advantages of Using Bulk Metal® Foil Resistors in High-Humidity Environments
All resistors that are based on nichrome, which is a category that includes both thin film devices and Bulk Metal Foil resistors, are susceptible to electro-chemical corrosion or etching when placed in a high humidity environment and powered with a very low wattage. But since the nichrome element of a Bulk Metal Foil resistor is hundreds of times thicker than the element in a thin film device with the same value, it will last much longer under these conditions. This video shows the actual etching process and survival times for thin film and foil nichrome resistive elements as they are tested in 100% humidity conditions.
Surface-mount resistors suffer physical stresses when exposed to high vibration or thermally unstable environments. Failure modes commonly occur in welds, solder joints, connectors, and terminations, ultimately resulting in circuit failure. In this demonstration, vibration-table-mounted boards are subjected to ±2° deflection 25 times per second and monitored for any ΔR > 0.1%. All the chip resistors failed in 2 to 12 minutes (8K to 16K cycles). But the Alpha MPP molded Bulk Metal® Z-Foil resistor with flexible terminations experienced over a million cycles with no change in resistance.
