A resettable fuse is a polymeric positive temperature coefficient (PPTC) device that is a passive electronic component used to protect against overcurrent faults in electronic circuits. The device is also known as a multifuse or polyfuse or polyswitch. . Beam deflection tube · Charactron · Iconoscope · Magic eye tube. Read about ‘F1/F2 polyfuses gone’ on elementcom. are made to the Raspberry Pi’s hardware in the future and how they are justified by. Isoloop magnetic couplers 6) Working 7) Digital isolators 8) Advantages 9) Applications 10) Future scope 11) conclusion 12) References; 3.
|Published (Last):||16 September 2008|
|PDF File Size:||20.11 Mb|
|ePub File Size:||9.99 Mb|
|Price:||Free* [*Free Regsitration Required]|
The effects of nonuniform current flow at the contacts can be analyzed using the same techniques used for diffused resistors ruture 5. Epi Pinch Resistors An epi pinch resistor resembles a base pinch resistor in that it consists of a resistive region pinched between two junctions to increase its sheet resistance.
This can produce xcope changes in resistance due to the movement of grain boundaries or the activation of incompletely incorporated dopants. These resistors should bc laid out on field oxide because any steps in the underlying surface may cause significant variability. For example, the resistor normally trimmed in a Brokaw bandgap31 connects between the emitter of an NPN transistor and ground.
As long as a few kilohms of resistance lie between the zaps and the remainder of the circuit, programming will generally cause no harm. The effects of bends in the resistor can be handled in the same manner as for the strip resistor.
Leads in single-level-metal designs must often route over HSR resistors for topological reasons. Zener zapping involves the formation of an aluminum-silicon alloy, and this in turn presumes that aluminum is directly touching the silicon. When power is removed, the heating due to the leakage current will stop and the PPTC device will cool. Not only does this impair the blowing of the fuses, but it also makes them prone to regrowth because sckpe material remains near them.
Batteries for Portable Devices. In practice, sheet resistances of diffusions are usually determined by empirical measurement instead of by computation.
This layout is less sensitive to variations in current flow near the sense points.
The act of programming a Zener is called zapping, so these Zeners are called zap Zeners, or Zener zaps. Trombone Slides Serpentine resistors can be adjusted by sliding turns inward or outward, a technique colorfully referred to as a trombone slide. Sliding contacts are easiest to implement for resistors without heads Figure 5.
A sliding contact can still be made as long as the material of the head has the same resistivity as the material of the body Figure 5.
This article presents the circuit of electronic eye. Please help improve this article by adding citations to reliable sources. These implants exhibit sheet resistances of 1 to depending upon implant dose, junction depth, and subsequent annealing conditions.
Thin-film resistors can be made from a wide variety of materials, the most common of which are nichrome a nickel-chromium alloy and sichrome a siliconchromium mixture. The emitter and base contacts should be placed as close as layout rules allow to facilitate the zapping process. N-well resistors without pinch plates are used for many of the same applications as base pinch resistors.
Second-metal leads can route over a resistor placed on first metal, but first-metal or poly leads should not route beneath a resistor placed on second metal because they may introduce nonplanarities in the resistor. These leads not only waste die area but can also pick up noise from other circuitry. For example, a merged HSR resistor divider connected to a 20V supply will experience severe mismatches.
Grebene’s value appears to be in error: Base and HSR diffusions: Serpentine resistors use the correction factors previously discussed. Emitter resistors need not be enclosed in a base region to isolate them from the surrounding tank because the N-epi sheet resistance is much larger than the emitter sheet resistance.
Resettable fuse – Wikipedia
High-sheet resistors are usually tweaked using sliding heads. Addison-Wesley,pp. Base pinch resistors are exceptions to the above rules since their values depend primarily on their sheet variation, and increased widths offer little benefit.
The current must bend upward to exit through the surface of the resistor, and it crowds toward the inside edges of the contacts as it does so.
Just as popyfuse money replaced specie-backed paper currencies, electronically initiated debits and credits will become the dominant payment modes, creating the potential for private money to compete with government-issued currencies. The junction depth of the HSR implant generally does not exceed 0. Comparison of Available Resistors length causes significant errors in the sense voltage.
Minimumwidth resistors of less than about may overheat during trimming, causing resistance variations and, in extreme cases, outright failures.