Traic is tha combination of two zener diodes in anti series.
43 Volts.
negative tempareture It depends on the reverse voltage. Up to about 5.6 volts, the zener has a negative temperature coefficient. Beyond 5.6 volts it begins to show a positive temperature coefficient.
A Zener Diode will continue to show its breakdown characteristics until it gets fried...for example a 5 volt zener will get fried at a breakdown voltage of about 6 volts..this happens because of the large amount of current flowing through the small diode which unfortunately the diode cannot handle.
Like a normal diode............. unless it includes a "back biased" diode to prevent conduction in this mode as is common in zener diodes rated at about 10 volts or more, then it acts as an open circuit.
The breakdown voltage point for a Zener diode is 17 volts
The difference is , the break down in a zener is desirable, well designed, expected, healthy and designed for a particular value. After breakdown, it can and is expected to maintain that condition for a long time. zener is optimized to work in this region.They are designed to have very low breakdown voltages. In contrast, the break down in a rectifier diode is undesirable, not well designed, not respected. This diode is optimized to work in the rectifier region and optimized for that. Breakdown region is avoided in normal operation. The breakdown voltage is normally very high, above 100 volts.
The zener region describes the area on the performance curve (a graph of voltage across versus current through the junction) of a zener diode. The diode acts like a "regular" diode in the forward biased direction. When some 0.7 volts or so is reached, forward current begins to climb rapidly as voltage is increased (for silicon diodes.) But in the reverse direction recall that as the diode is reverse biased, a small amount of current will flow (because of minority carriers). This "trickle" of current will continue until the "zener voltage" is reached, and then the diode will begin to conduct heavily. On the graph, this is the zener region. Zener diodes can be made to breakdown at a specific voltage, and their ability to conduct reverse current can be increased by manufacturing a larger diode. That means there are a range of voltages and wattages of zener diodes available. Wikipedia has more information and that graph. Use the link provided to get there.
If you are talking about reverse biasing a diode, then you are talking about a zener diode. A zener diode, like a normal diode, has a forward bias around 0.7 volts (depending on current and temperature). Using Ohm's law, you can calculate the effective resistance of the diode in forward bias. (Example: 0.7 volts, 100 milliamps, 7 ohms) In reverse bias, however, a zener diode conducts at a different voltage. This is what zener diodes do. Using Ohm's law, you will get a different effective resistance of the diode in reverse bias, because it is dropping a different voltage. (Example: 5.6 volts, 100 milliamps, 56 ohms) It should be noted that attempting to measure the resistance of a diode does not make sense, because it is a non linear device. You should instead consider the current to voltage curve to understand the diode, be it regular or be it zener.
Zener breakdown is the phenomena wherein the Zener diode experiences reverse breakdown at a much lower voltage than a normal diode, which may breakdown in excess of 100 volts, depending on the type. This is useful because the Zener will hold the same voltage after breakdown, regardless of the input voltage, making them excellent for voltage controlled switches and references.
A zener diode is designed to allow a current to flow through it in a direction that is reverse to the normal flow of current that would occur if it were used as a rectifier. Current can flow through a zener diode in both directions. In the forward direction, current will flow at a low voltage, usually about 1 volt. In the reverse direction, no current will flow until the voltage impressed across it is equal to the zener voltage. At this point, a current will flow and an extremely small increase in voltage will cause a large increase in current. Most importantly, it should be noted that the current flow through the zener diode is in the reverse direction to that of a normal rectifier. With the application of sufficient reverse voltage, a p-n junction will experience a rapid avalanche breakdown and conduct current in the reverse direction. Valence electrons which break free under the influence of the applied electric field can be accelerated enough that they can knock loose other electrons and the subsequent collisions quickly become an avalanche. When this process is taking place, very small changes in voltage can cause very large changes in current. The breakdown process depends upon the applied electric field, so by changing the thickness of the layer to which the voltage is applied, zener diodes can be formed which break down at voltages from about 4 volts to several hundred volts.
The resister always being used to save components to damage by absorbing extra voltages, diode works on 0.7 volts n usually having 15 volts from the source so extra voltages drops across the resister and it works safely.
An ideal zener diode will have zero reverse current while the reverse voltage is less than the zener voltage. Once the voltage rises above the zener voltage, the maximum reverse current will become infinite (the device will become a short). On a graph with voltage along the X axis and current along the Y axis, this would be represented by a straight vertical line crossing through the zener voltage. A practical zener diode has a monotonic change from zero current at zero volts, rising gradually as the voltage approaches the zener voltage from below, then rising sharply as the voltage is around the zener voltage. This means that with reverse voltage applied even slightly below the zener voltage there will be some current flow. This can be a problem in some circuits if not understood and accounted for.