Steel film resistors have a skinny steel layer as a resistive component on a non-conducting physique. They’re amongst the commonest forms of axial resistors. Different film kind resistors are carbon film and thick and thin-film resistors. In most literature referrals to the steel film, normally, it’s a cylindrical axial resistor.
Nonetheless, thin-film chip resistors use the identical manufacturing precept for the steel layer. The looks of steel film resistors is much like carbon film resistors, however their properties for stability, accuracy, and reliability are significantly higher. Steel film resistors are axial resistors with a skinny steel film as a resistive component. The skinny film is deposited on normally a ceramic physique.
METAL FILM RESISTOR CONSTRUCTION
The resistive component is a skinny steel layer that’s normally sputtered (vacuum deposition) on a cylindrical excessive purity ceramic core. Generally different strategies than sputtering are used. The deposited steel is artificially aged by protecting it for a protracted interval at a low temperature. This leads to higher accuracy of the resistor. The resistance materials is commonly nickel-chromium (NiCr), however for particular purposes additionally different alloys are used comparable to tin and antimony, gold with platinum, and tantalum nitride. The steadiness and resistance are strongly depending on the thickness of the steel film (50-250 nm).
A bigger thickness of the layer leads to higher stability and decrease resistance worth. On each ends, a steel cowl is pressed with the connection leads. After this, the specified resistance is achieved by chopping a spiral-shaped slot within the skinny steel layer. That is normally executed by lasers, whereas prior to now sandblasting and grinding strategies have been used. Carbon film resistors use the identical approach to trim the resistance.
The resistor is roofed with a number of coating layers which can be baked individually. The coating protects in opposition to moisture and mechanical stresses and ideally has excessive dielectric energy. The resistor worth is marked by shade code bands or with textual content. The steel film resistors can be found with tolerances of 0.1, 0.25, 0.5, 1, and a pair of%. The Temperature Coefficient of Resistance is normally between 50 and 100 ppm/Okay.
- RESISTOR TYPES
- Top 12+RESISTOR PROPERTIES & types
- What Is ohms Law & KIRCHHOFF’S CIRCUIT Top 3? Types
- WHAT IS A RESISTOR? & Top 5 Types Of FUNDAMENTALS
METAL FILM RESISTOR TYPICAL APPLICATIONS
Steel film resistors have good traits for tolerance, stability, and TCR. Moreover, the resistors function low noise properties and excessive linearity due to a low voltage coefficient. Due to this fact, in circuits the place tight tolerance, low-temperature coefficient and low noise properties are vital, typically steel film resistors are used. Examples of purposes are energetic filters or bridge circuits.
METAL FILM RESISTOR RELIABILITY
For a great reliability, steel film resistors are usually operated between 20 and 80 p.c of their specified energy score. Reliability is usually elevated by derating 50%. Nonetheless, in very particular conditions, at decrease than 20% of the facility score in a damp surroundings the reliability decreases. In comparison with wirewound or carbon composition resistors, these resistors are simpler broken by voltage surges and energy overloads.