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What happens when Zener diode is reversed?
This is because when the reverse voltage applied across the zener diode exceeds the rated voltage of the device a process called Avalanche Breakdown occurs in the semiconductor depletion layer and a current starts to flow through the diode to limit this increase in voltage.
What is avalanche effect of Zener diode?
Avalanche breakdown involves minority carrier electrons in the transition region being accelerated, by the electric field, to energies sufficient for freeing electron-hole pairs via collisions with bound electrons. The Zener and the avalanche effect may occur simultaneously or independently of one another.
Why are Zener diodes heating up and smoking?
Zener diode is heating due to power dissipation. More the power dissipation more the heat, similar to resistor, for example: 2 ohms resistor carrying current of 1A is dissipation 2W of power. Smoking is due to “excess power dissipation”, i.e you are crossing the limit of maximum power withstanding capacity of Zener.
Why do you use a diode with a heater?
One solution is to use a diode in series with the heating element. The diode will reduce the applied energy to the heater for any given voltage and allow a larger lower resistance heating element to be used. Naturally, this is not applicable to DC-powered heaters. A diode blocks half of each cycle in the incoming AC voltage wave.
How much power can a diode dissipate before it blows?
Just like any component, diodes can only dissipate so much power before they blow. All diodes should list maximum current, reverse voltage, and power dissipation. If a diode is subject to more voltage or current than it can handle, expect it to heat up (or worse; melt, smoke,…).
Why are my LEDs heating up and smoking?
Your diode is smoking because the current through it is excessive; you are damaging it. It is not a good test either since voltage drop over a diode depends on the current and when the current is higher the drop is larger (with real Neopixel load the drop over a diode will be smaller and you’ll overload the LED).