“ZNR” Transient/Surge Absorbers “ZNR” Transient/Surge Absorbers ZNRs are zinc-oxide nonlinear resistors whose resistance changes as a function of the applied voltage. These basic characteristics of ZNR express by varistor voltage and clamping voltage (or voltage ratio). The ZNR utilizes a ceramic element composed of zinc oxide and several kinds of metal oxide additives that have been sintered at relatively high temperature. The ZNR has a bilateral and symmetrical V-I characteristics similar to back-to-back zener diode and unparalleled large peak current capability so it can be used for absorption of transient voltage, suppression of pulse noise and as an arrester element and circuit voltage stabilization. Explanation of technical terms 2. Maximum Peak Current Specification which specified how much surge current surge absorber can endure is maximum peak current. This characteristic expresses a current value having standard wave form shown in figure 2. In case of different waveform from the standard one, the specifications shall be determined by reffering to impulse life ratings. 100 90 Voltage log Maximum Clamping Voltage Current(%) Varistor Voltage 1. Voltage-Current Characteristics Figure 1 shows voltage-current characteristics of ZNR. The axis of abscissas is logarithm of current and the axis of ordinates is logarithm of voltage. Characteristics, voltage value at 1mA(principle) is used, calling varistor voltage. In case of surge absorber which utilizes at large current region because of voltage at specified current is used, calling clamping voltage. Max. Nom. Min. Maximum Leakage Current -3 10 A 50 10 0 8 µs Current log 20 µs Fig. 1 Example of V-I Characteristic of ZNR Time Fig. 2 Standard Impulse Current Waveform (8/20 μs) Note ✽ ZNR “Zinc Oxide Nonlinear Resistor” is a trade mark of voltage dependent resistor elements by Panasonic. ZNR is in some cases named Metal Oxide Varistor “MOV” 3. Clamping Voltage Varistors have an abitity to limit a high voltage surge like lightning. We call this limited voltage as “Clamping Voltage”. “Clamping Voltage” is measured by voltage between two therminals using standard impulse current waveform (8/20 µs) shown in fig.2. To avoid an exothermic influence. Lightning Voltage Voltage Voltage Clumping Voltage by ZNR Time Time Fig. 3 Example of impressing pulse and clamping Voltage Design and specifications are each subject to change without notice. Ask factory for the current technical specifications before purchase and/or use. Should a safety concern arise regarding this product, please be sure to contact us immediately. 03 Jan. 2015