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High Precision Axial Leaded Cylindrical Fixed Metal Film Resistor 1/8W 1/4W 1/2W
Description Of The Metal Film Resistor 1/8W 1/4W 1/2W
Metal film resistors are widely used resistors so far, with high precision, stable performance, simple and lightweight structure. It plays an important role in the electronic industry and military aerospace under high-precision requirements.
Metal film resistors are a kind of film resistors (Film Resistors). It uses high-temperature vacuum coating technology to closely attach nickel-chromium or similar alloys to the surface of the porcelain rod to form a film. After cutting and adjusting the resistance value to achieve the final required precision resistance value, it is then cut with appropriate joints and coated on the surface Sealed and protected by epoxy resin. Because it is a lead type resistor, it is convenient for manual installation and maintenance, and is used in most household appliances, communications, and instruments.
Advantages Of The Metal Film Resistor 1/8W 1/4W 1/2W
* Low cost.
* Generates less noise than carbon composition resistor.
* Wide operating range.
* Long term stability.
* Low tolerance.
* Low temperature coefficient of resistance hence the resistance of
the metal film resistors does not change easily with change in
temperature.
* Very small in size.
APPLICATIONS Of The Metal Film Resistor 1/8W 1/4W 1/2W
• Industrial
• Telecommunication
• Medical equipment
• Automotive
Electrical Performances Of The Metal Film Resistor 1/8W 1/4W 1/2W
Type | Rated power | Max working voltage | Max overload voltage | Dielectric withstanding voltage | Resistance Range(Ω) | |
Normal size | MF1/8W | 0.125W | 200V | 400V | 300V | 1Ω~1MΩ |
MF1/4W | 0.25W | 250V | 500V | 500V | 1Ω~10MΩ | |
MF1/2W | 0.5W | 350V | 700V | 700V | 1Ω~10MΩ | |
MF1W | 1W | 500V | 800V | 900V | 1Ω~10MΩ | |
MF2W | 2W | 500V | 1000V | 1000V | 1Ω~10MΩ | |
MF3W | 3W | 500V | 1000V | 1000V | 1Ω~10MΩ | |
MF5W | 5W | 500V | 1000V | 1000V | 1Ω~10MΩ | |
Small size | MF1/4WS | 0.25W | 250V | 400V | 300V | 1Ω~10MΩ |
MF1/2WS | 0.5W | 350V | 700V | 500V | 1Ω~10MΩ | |
MF1WS | 1W | 350V | 800V | 700V | 1Ω~10MΩ | |
MF2WS | 2W | 500V | 1000V | 1000V | 1Ω~10MΩ | |
MF3WS | 3W | 500V | 1000V | 1000V | 1Ω~10MΩ | |
MF5WS | 5W | 500V | 1000V | 1000V | 1Ω~10MΩ |
Power derating curve Of The Metal Film Resistor 1/8W 1/4W 1/2W
Resistor body color Of The Metal Film Resistor 1/8W 1/4W 1/2W
Normal size | Small size | ||
Type | Color | Type | Color |
MF1/8W,MF1/4W, MF1/2W,MF1W, MF2W,MF3W, MF5W | Sky blue | MF1/4WS ,MF1WS, MF2WS,MF3WS, 5WS | Sky blue |
Size Of The Metal Film Resistor 1/8W 1/4W 1/2W (mm)
Type | Dimensions | |||||
Normal Size | Small Size | I | L | ψD | ψd | H |
MF1/8W | MF1/4WS | 60 | 3.2±0.5 | 1.8±0.5 | 0.43±0.05 | 28.0±2.0 |
MF1/4W | MF1/2WS | 60 | 6.5±0.5 | 2.3±0.5 | 0.45±0.05 | 28.0±2.0 |
MF1/2W | MF1WS | 60 | 9.0±0.5 | 3.2±0.5 | 0.50±0.05 | 28.0±2.0 |
MF1W | MF2WS | 60 | 11.5±1.0 | 4.5±0.5 | 0.7 0±0.05 | 25.0±2.0 |
81 | 11.5±1.0 | 4.5±0.5 | 0.7 0±0.05 | 35.0±2.0 | ||
94 | 11.5±1.0 | 4.5±0.5 | 0.7 0±0.05 | 42.0±2.0 | ||
MF2W | MF3WS | 60 | 15.0±1.0 | 5.0±0.5 | 0.70±0.05 | 23.0±2.0 |
70 | 15.0±1.0 | 5.0±0.5 | 0.70±0.05 | 28.0±2.0 | ||
81 | 15.0±1.0 | 5.0±0.5 | 0.70±0.05 | 33.0±2.0 | ||
94 | 15.0±1.0 | 5.0±0.5 | 0.70±0.05 | 40.0±2.0 | ||
MF3W | MF5WS | 94 | 17.5±1.0 | 6.0±0.5 | 0.70±0.05 | 38.0±2.0 |
MF5W | 94 | 24.5±1.0 | 8.0±0.5 | 0.70±0.05 | 35.0±2.0 |
Factors to consider when choosing a resistor
Choosing a resistor should consider at least the following five factors: resistor type, rated power, rated voltage, temperature coefficient, and accuracy.
1, Resistor type
There are many types of resistors, including chip resistors, carbon
film resistors, wire wound resistors, metal film resistors, metal
oxide film resistors and so on. SMD resistors are small in size and
suitable for large-scale integrated circuits. There are precision
and common resistors. The circuits are very common; carbon film
resistors have good stability, low negative temperature
coefficient, good high-frequency characteristics, and are less
affected by voltage and frequency, and noise electromotive force is
relatively small. Small, wide resistance range, but not high
precision; wire wound resistors have a low temperature coefficient,
high resistance precision, good stability, heat resistance and
corrosion resistance, mainly used as precision high-power
resistors, but poor high-frequency performance; Metal film
resistors have higher accuracy, better stability, and lower
temperature coefficient than carbon film resistors; metal oxide
film resistors are stable at high temperatures, resistant to
thermal shocks, and have strong load capacity.
Each type of resistor has a certain operating frequency. When
choosing a resistor, you can choose the type of resistor according
to the frequency of the circuit. Especially in high-frequency
circuits, you should choose a resistor with better high-frequency
performance, and choose a higher Small dielectric loss resistance
and package type size, etc.
2, Resistor rated power
The rated power of the resistor is determined by the hot spot
temperature that the resistor bears, because the resistor is
greatly affected by the ambient temperature. Therefore, in the
circuit, it is necessary to consider the long-term working diameter
temperature of the electronic product and the maximum temperature
and the lowest temperature, so as to calculate how much resistance
power is. Generally, the power used when designing the circuit is
less than 1/2 of the rated power. Power. For example, if the actual
power of the resistor reaches 0.4W, then a resistor with a rated
power of 1W can be selected. This is to leave enough margin in the
circuit for derating to improve circuit reliability.
3, resistance rated voltage
When the rated power of the resistor is constant, the rated working
voltage increases with the increase of the resistor R, but with the
increase of the voltage, the current density flowing through the
resistor will also increase, resulting in serious local heating of
the resistor, and the resistor is prone to aging and failure over
time.
4, resistor temperature coefficient
Under the influence of the ambient temperature and the heat of the
resistor itself, the resistance value of the resistor will drift,
which is what we call temperature drift. The temperature
coefficient of resistance mainly depends on the resistivity of the
resistor material and the ambient temperature. General film
resistor
The temperature coefficient of and wire-wound resistors is
relatively small, while that of synthetic film resistors is
relatively large. In circuits requiring relatively high resistance
stability and circuits with very large environmental temperature
differences, the influence of the temperature coefficient of
resistance on the circuit must be fully considered.
5. Resistor accuracy
Resistance accuracy is also an important consideration for
selecting hardware circuit resistance. Generally, it is not
necessary to use high-precision resistors for circuits that are not
strict in resistance. However, for instruments, current measurement
circuits, voltage detection circuits, etc., the current or other
Circuits that have a great impact on resistance fluctuations
require precision resistors, and some circuits even use 0.01% high
precision resistors.