What do the numbers on a varistor mean?

The energy rating for the varistor is often defined using standardised transients. The transient is expressed in the format x/y where x is the time for the transient rise and y is the time to reach its half peak value. Typical formats are 8/20 and 10/1000.

How can you tell a good varistor?

Touch one meter probe to the free varistor lead and the other probe to the connected lead. Read the resistance on the meter. If it reads nearly infinite resistance, the varistor is still good. If it reads very low resistance, the varistor is blown.

Is there polarity on a varistor?

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.

How does a multimeter detect metal oxide varistor?

Turn the multimeter on and set its function knob to read resistance. 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.

What is the purpose of a varistor?

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.

Should a varistor have continuity?

A continuity test shouldn’t cause a beep, because a varistor has much greater resistance than, say, a fuse. Try it on the Ohms range of the meter. The varistor is presumably an inrush current limiter whose resistance drops as it heats up.

How do you calculate a varistor?

The simplest ways of determining the current duration are simulation or measurement (τ = t*r). The time constant can also be calculated to an approximation with equation 13. Here the varistor resistance of voltage class K20 is calculated for 1 A.

What is the peak voltage of the 10d471k varistor?

So peak voltage is 308V = 220V x 1.4 (VPeak = VRMS × √2) This MOV 10D471K is having 300V AC RMS rating. So its suitable for 220V AC mains applications.

Which is sunrom varistor MOV for 220V AC?

10D471K – Varistor MOV for 220V AC Sunrom Product Code for Ordering: 4885 This MOV is suitable for 220V AC line protection in a typical electronic devices against voltage surges and spikes, such as those generated by inductive switching transients.

What kind of electrical behavior does a varistor have?

Varistor are voltage dependent, nonlinear device which have an electrical behavior similar to back-to-back zener diodes. CNR series zinc oxide varistor are nonlinear resistors, consisting main of zinc oxide and several kinds of metal oxide additive.

What is the function of a CNR series varistor?

CNR series zinc oxide varistor are nonlinear resistors, consisting main of zinc oxide and several kinds of metal oxide additive. They are bilateral and symmetrical V-I characteristics curve and unparalleled large peak current capability are used for absorption of transient voltage, suppression of pulse noise and circuit voltage stabilization.