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Ultra Metal Film Resistor

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Resistor 超小型金屬膜電阻

PDF File  Data Spec Ultra Miniature Metal Film Resistor - UMR Series

Resistor INTRODUCTION
The UMR Series flame-proof type miniature Metal Film Resistors are manufactured by vacuum depose it metal film on
high thermal conductivity and specific gravity Rosenthal ceramic or same grade Japans rods. The both ends of
ceramic are coated with precision mixed metals which help to prevent against noise, and to provide low TCR
and low Tol precision resistors the can meet MIL and JIS requirement.
Utilizing a 95~98% of AI ceramic cores and combined a special cutting technology inside, this resulting superior
resistors give excellent heat dissipation, stable performance and significantly up-grade the power rating.
This specially designed resistors are widely used by the industries of communication devices, meters,
high-class, audio equipments and precision military defending facilities as well.
Resistor EXTERNAL DIMENSIONS SINLOON®
STYLE DIMENSION (mm)
L ΦD H Φd
UMR-01 3.3±0.4 1.8±0.3 28±2 0.5±0.05
UMR-02 6.3±0.5 2.3±0.3 28±2 0.6±0.05
UMR-03 6.3±0.5 2.3±0.3 28±2 0.6±0.05
UMR-10 6.3±0.5 2.3±0.3 28±2 0.6±0.05
UMR-20 9.0±0.5 3.2±0.5 26±2 0.6±0.05
UMR-30 15.5±1.0 5.0±0.5 32±2 0.6±0.05
The type designation shall be in the following form and as specified.
Resistor RATED POWER
Type Power Maximum Voltage Dielectric withstanding Resistance
Working Overload Voltage (AC) Range
UMR-01 0.4W 200V 400V 300V 1R~10MΩ
UMR-02 0.5W 250V 500V 500V 1R~10MΩ
UMR-03 0.6W 250V 500V 500V 1R~10MΩ
UMR-10 1W 250V 500V 500V 1R~10MΩ
UMR-20 1.8W 350V 700V 700V 1R~10MΩ
UMR-30 3W 500V 1KV 1KV 1R~10MΩ
Temp. Coefficient (by Type) ±50ppm, ±100ppm
Resistor FEATURES
Resistance Tolerance: ±1%, ±2%, ±5%.
Excellent long-term stability.
High power-to-size ratio for significant space saving.
Variety of packing: bulk, strip pack, 26mm and 52mm tape and reel, cut and foramen.

 

 
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Newsflash

LED 光度控制

LED驅動芯片 LED 光度控制

 

LED 光度控制

要改變LED的光度有兩種方式:直接改變流過LED的電流,或以快速開關LED以達至改變LED的平均功耗。

要設定LED光度,最直接的方法就是設定LED的電流,LED光度與電流並不成線性關系,要知道什麼的電流值才可以達到預期的光度,可以參考生產商資料提供有關電流與光度關係的資料,又或以可變電流源推動LED下找出合適電流值。

LED光度與電流並不成線性關系,若在使用中須要調變光度,以線性電路產生所需控制訊號的改變較難達至預期相對應的光度變化。

D是佔空比,D=0%LED全閉,D=100%LED全導通,改變佔空比可任意調變LED光度  D 是佔空比

另一改變LED光度的方法是快速開關LED,以脈衝寬度調製(Pulse width modulation - PWM),在每個重複的開關週期內,改變導通與關閉的時間比例(也即是占空比),改變流經LED的平均電流(平均功耗),從而控制LED的光度,由於LED導通時工作在較大電流,偏壓比連續導通高,因此消耗在控制元件上的功耗較少,效率略高。只要閃爍頻率高於人眼的視覺暫留,LED看起來就象連續發光一樣。而只要改變占空比,LED的光度就能在使用中調變。

在白色LED使用脈衝寬度調製控制LED光度有另一好處,白色LED的色溫隨電流強弱而轉變,在脈衝寬度調製控制下,導通電流在不同光度下都不變,因此能在不同光度保持色溫不變。