Electrical Engineering Stack Exchange
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Questions tagged [zener]

Zener is an effect in semiconductors, the name of a diode that uses that effect and more generally any diode that has similar characteristics to a Zener diode.

Zener is an effect in semiconductors, the name of a diode that uses that effect and more generally any diode that has similar characteristics to a Zener diode.

Zener diodes have the unique characteristic of a reliable reverse bias breakdown voltage and are often used as simple voltage regulators or level shifters.

Zener breakdown is a distinct effect and in common usage is any diode that has a fixed reverse breakdown are called "Zeners" even if the mechanism is different.

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Why is a Zener diode in a crowbar configuration dropping the input voltage?

simulate this circuit – Schematic created using CircuitLab I'm trying to hook up a Zener diode in order to add some measure of protection (fused "crowbar") to a circuit that includes a loop powered oxygen sensor with output read by a GHI Cobra…
Matt
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What's the equivalent zener voltage of two parallel zeners?

Assume we have two zeners connected in parallel, one with a zener voltage of x volts, and one with a zener voltage of y volts. What will be the equivalent zener voltage of the circuit?
user17592
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Is my zener diode labeled wrong, or am i seeing a strange failure mode?

I'm experimenting with a power supply circuit to bring 24VAC down to 5VDC. I have an L7805CV, but rectified (a bridge) and smoothed (a 33μF electrolytic), the input is still \$40V_{peak}\$, which is more than the max input voltage the regulator can…
Rob Starling
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Zener effect and avalanche effect

I was wondering whether there is a difference between Zener effect and avalanche effect? How do they differ?
Inquisitive
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Current distribution for parallel zeners

Suppose you've got two 5V1 zeners in parallel. Due to slight differences between the two parts (tolerance on zener voltage), one of them will conduct more current. simulate this circuit – Schematic created using CircuitLab The one consuming most…
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Why does the voltage of a zener diode match the voltage at Vout?

In this circuit, if: Vin = 9V Vz = 5V I understand that Vout will be 5V. Does that have to do with Kirchhoff's Voltage Law? How does the zener diode, if it drops 5V to ground, cause Vout to also be 5V?
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Differential resistance for a zener

I'm reading the BZX79 datasheet. On page 4 it lists differential resistance at 1mA and 5mA. For instance for the 3V version differential resistance is typical 325\$\Omega\$ at 1mA. Would that mean that a 1mA rise in current would result in a 325mV…
Federico Russo
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Why is zener current preferred to be more than load current in a voltage regulator?

In a simple Zener Voltage Regulator, such as this Why should current passing through the zener diode(zener current) be more than the current passing through the load(load current)? or No such conditions exist P.S. In my school notes, it was simply…
Cheeku
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Zener diode equivalent circuit

When a diode is forward biased it has a voltage drop of 0.7/0.3 volts across it because of the depletion region. Therefore the equivalent circuit of the diode is represented as a battery and a bulk resistance of diode. I am facing a problem in…
Alex
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Selecting correct zener diode

Hi I'm trying to build a PSU based on a design which has it's maximum input voltage 15v. However mine is rectified from 200VA 24Vrms centre tapped transformer. I need to use a zener diode to ensure the voltage doesn't go above 12V for the TLC272…
Ageis
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What are the electronics components that have characteristics like Neon Lamp?

Neon lamps have higher breakdown voltage than its operating voltage. When brokendown, it acts like a zener at its operating voltage.
user1502776
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USBLC6-2 Zener Breakdown Voltage

Im designing a simple usb application and I used this USBLC6-2 for ESD protection and voltage surge on the Vusb. On the datasheet it says that the breakdown voltage is min 6V, however I did some test for this if this is for real. I input a 10V on…
jasp
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Zener diode setup

Since most lower voltage zener diodes operate at 5ma and require a resistor to provide it, what happens when you add a small resistance load across the zener and there is no longer 5ma for the zener to keep the voltage regulated ? In other words,…
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Is this way of sizing the series resistor for Zener regulator correct?

This is a completely made up imaginary question to ask the question easier. Let's say I have a 0.1W 5V Zener diode. And I want to use this to regulate from 9V to a 10k load. I draw this as in the below diagram: So above if I want to set Rs. I do…
user1245
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How good is to use this zener diode for reverse polarity protection?

In the following circuit how does the zener diode D1 provide reverse polarity protection? Lets say V+=12V and V-=-12V and the zener is 36V zener. It means for correct polarity zener will not pass any current since it sees 24V across itself. But in…
user16307
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