What is the difference between varistor and capacitor?
is that varistor is an electronic component having a variable resistance; used to protect circuits against power surges while capacitor is (electronics) an electronic component capable of storing an electric charge; especially one consisting of two conductors separated by a dielectric.
How do I test a MOV varistor?
Touch the meter probe tips to the MOV’s leads and measure its resistance. If it has a resistance much under 100 ohms, it has blown. Desolder and remove the remaining lead and remove the MOV from the equipment. If the part has resistance over one million ohms, it is still good.
How is the dissipation of an AC varistor calculated?
Case 2—Calculating ac Dissipation: When a sinusoidal alternating voltage is applied to a varistor, the dissipation is calculated by integrating the VI product. A suitable expression is as follows: Transient energy ratings are quoted in Joules.
How are varistors different from transient suppressor diodes?
Compared with transient suppressor diodes, varistors can absorb much higher transient energies and can suppress positive and negative transients. Furthermore, against crowbar-type devices, varistor response time is typically less than a nanosecond, and devices can be built to withstand surges of up to a 70,000A surge.
Which is better a varistor or normal voltage?
The higher the nominal voltage of the selected varistor compared with the normal circuit operating voltage, the better its reliability is over time, as the device is able to withstand more surge currents without degrading performance. The disadvantage is a reduction in the level of protection offered by an over-specified varistor.
What kind of applications can varistors be used for?
For example, varistors now offer a cost-effective solution for low-voltage logic requiring a low protection level and low standby current, as well as for ac power line and high capacity, utility-type applications.