What is the leakage current in Zener diode?
When a diode is reverse biased, the width of the depletion region increases. It is seen that in a reverse-biased diode, some current flows through the depletion region. This current is called leakage current. Leakage current is dependent on minority current carriers.
What is Zener reverse leakage current?
Reverse leakage current in a semiconductor device is the current from that semiconductor device when the device is reverse biased. Hence, it is also called reverse saturation current. The term is particularly applicable to mostly semiconductor junctions, especially diodes and thyristors.
How does a Zener diode fail?
Zener diode regulator circuit, Zener voltage = 12.6V). Interestingly enough, when Zener diodes fail due to excessive power dissipation, they usually fail shorted rather than open. A diode failed in this manner is readily detected: it drops almost zero voltage when biased either way, like a piece of wire.
How leakage current is produced?
Ac leakage current is caused by a parallel combination of capacitance and dc resistance between a voltage source (ac line) and the grounded conductive parts of the equipment. The leakage caused by the dc resistance usually is insignificant compared to the ac impedance of various parallel capacitances.
Is leakage current and saturation current same?
Reverse saturation current terminology is generally used in diode whereas leakage current is used in BJT. But both are more or less indicates the same quantity, i.e leakage current and reverse saturation current is flowing due to the minority carriers.
What is zener breakdown voltage?
A normal p-n junction diode allows electric current only in forward biased condition. This sudden rise in electric current causes a junction breakdown called zener or avalanche breakdown. The voltage at which zener breakdown occurs is called zener voltage and the sudden increase in current is called zener current.
How does zener breakdown occur?
Zener breakdown occurs when we apply reverse bias to a heavily doped diode. For heavily doped junctions, when reverse voltage is increased, the electric field at junction increases (as more carriers are present now to create such a pull) which causes covalent bonds to break.
How does a zener barrier work?
A zener barrier is a simple device where the voltage & current (Power, Energy) is limited into the hazardous area. The voltage is limited/clamped by a zener diode and the current limited by an output resistor. The fuse is there to protect the zener diode. The key to safety is the Intrinsically safe earth.
What causes the Zener current to go up?
If, however, the reverse bias is increased until it reaches the breakdown region, then a small reverse voltage increase causes a considerable increase in leakage current; the reverse current is then called the Zener current.
Why does a Zener diode have leakage spec?
The reason for this is that leakage (in it’s various forms , Band to band, tunnelling, Hopping) is driven to a first order by impurities and defects which are by definition random. Principally these devices are not usually operated in any really different mode other than as Zeners, so this is measurement is more of a reality check.
What kind of current does a Zener barrier conduct?
The Zener barrier conducts a maximum of 10 µA (1 µA) leakage current so long as the supply voltage is less than 25.5 V. This is normal and has very little effect on the load. If the voltage exceeds 25.5 V, the zener diodes start to conduct more current.
What is the maximum voltage of a Zener?
Voltage Vz: The Zener voltage refers to the reverse breakdown voltage—2.4 V to about 200 V; can go up to 1 kV while the maximum for the surface-mounted device (SMD) is about 47 V). Current Iz (max.): Maximum current at the rated Zener voltage Vz—200 uA to 200 A).