Is a varistor a diode?
A varistor is an electronic component with an electrical resistance that varies with the applied voltage. Also known as a voltage-dependent resistor (VDR), it has a nonlinear, non-ohmic current–voltage characteristic that is similar to that of a diode.
What is a varistor used for?
Varistors are used to protect a circuit from high voltage surges. When a high voltage surge is applied to a circuit, the outcome is usually catastrophic to the circuit. A capacitor may be installed across the signal lines.
How does a varistor fail?
Under different current conditions, failure modes include electrical puncture (see Figure 4), physical cracking (see Figure 5), and thermal runaway. Cracking happens because varistors are basically a ceramic material, and hitting them with a sharp high-amplitude surge is like hitting a dinner plate with a hammer.
Are varistors bidirectional?
Varistors are bidirectional components suitable for both AC and DC circuits. They come in different design packages.
Does varistor have polarity?
Does a varistor have polarity? In the case of metal oxide varistor, a zinc-oxide layer is basically sandwiched between two metal electrodes. As a result, there is no polarity.
What does MOV stand for?
|MOV||QuickTime Movie (file extension)|
|MOV||Metal Oxide Varistor|
Do varistors have polarity?
How do you identify a varistor?
A gadget may have thousands of transistors, resistors and other components, but only one or two varistors. While it may look similar to a capacitor, you can identify the device by its color, markings and location. The MOV will always be close to the equipment’s power supply and wired to a fuse.
How do I know if my varistor is bad?
Open the case with the screwdrivers and locate the varistor. It is usually a brightly coloured disk the size of a coin. The varistor will likely be wired to a fuse holder. If the varistor is visibly burnt through or broken, it is bad; replace it.
Why does MOV fail?
This failure mode can be caused by long-duration overvoltage, such as switching from a reactive load or thermal runaway of the MOV connected to the ac mains. Open circuit failures are possible if an MOV is operated at steady state conditions above its voltage rating.
Are MOV polarity sensitive?
Are MOVs sensitive to polarity? A. No. Since MOVs provide bidirectional clamping, they are not a polarized device.
Is MOV better than MP4?
MP4 are typically more compressed and smaller in size, while MOV files are often higher in quality and larger in size. MOV files are better for video editing on a Mac, since they’re specifically designed for QuickTime.
How can I compare a TVS diode with a varistor?
The immediate differences I see are: The varistor is marginally cheaper The varistor specifies a maximum working voltage much, much smaller than its clamp voltage. There seems to be no maximum working voltage on the diode, only the breakdown voltage. The diode is well-specified, and includes many graphs of its I/V characteristics.
Is there a maximum working voltage on a varistor?
The varistor specifies a maximum working voltage much, much smaller than its clamp voltage. There seems to be no maximum working voltage on the diode, only the breakdown voltage. The diode is well-specified, and includes many graphs of its I/V characteristics.
What’s the difference between Zener and TVS diodes?
TVS diodes on the other hand are a combination of P-type and N-type semiconductors. They are silicon-based ESD protection components. Some diodes also use Au wire etc. The resistance value of both chip varistors and TVS diodes changes greatly depending on the applied voltage.
When does a varistor become functionally degraded?
As these pulses occur, the “clamping voltage” it provides during each event decreases, and a varistor is typically deemed to be functionally degraded when its “clamping voltage” has changed by 10%.