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Questions tagged [zener]

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. Often used as simple voltage regulators or level shifters. Zener breakdown is a distinct effect common usage is any diode that has a fixed reverse breakdown are called "zeners" even if the mechanism is different.

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Can a Zener diode that protects a switch against inductance when the switch opens, affect turn on speed of the valve when you close it again?

As you probably know, in the applications that the turn off speed of the solenoid valves are crucial, the simple flyback diode is not effective. Some people put a resistor in series with the flyback ...
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When/why would you use a Zener diode as a flywheel diode (on the coil of a relay)?

I have just been cogitating on the tutorial at http://www.electronics-tutorials.ws/io/io_5.html, and in the discussion of flywheel diodes it includes this sentence without further elaboration: As ...
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How does a zener diode and a resistor regulate voltage?

I'm having trouble understanding the simple voltage regulator that can be built using a zener diode (from section 2.04 in the Art of Electronics). I know that it would be better to use amplifiers, et ...
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How to decide between a TVS or Zener diode for overvoltage protection?

I'll leave my specific circuit out of this for a more broad question: What criteria does one use when deciding whether to use a Zener diode or a transient voltage suppressor, for overvoltage ...
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Why does temperature modify the characteristics of a diode?

Everyone knows that temperature affects every semiconductor device you can think of, and diodes are no exception. From the below graph, we can see that the temperature has marked effects on pn ...
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At what current and voltage do typical resistors explode?

I don't have an explosion chamber, so I cannot test critical values. If you explode resistors with too high current-voltage combination, does it damage your equipment, such as multimeter and DC-...
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“A zener with series diode”?

So I'm still reading The Art of Electronics Third Edition. On P.39, when dealing with indicative "kick", I found this sentence: For the fastest decay with a given maximum voltage, a zener with ...
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in zener diode current source, to provide constant current, what resistor, etc do I have to use?

I have a load that has varying resistance and want to know the change of resistance by measuring the voltage with constant current. The figure below is known to provide constant current. But I have no ...
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Why do we connect a resistor before a Zener diode?

Why do we need a resistor in a Zener diode circuit, like in the diagram below? I understand it is to limit the current but how so, and why do we need it for a Zener diode? Does selecting different ...
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Zener Noise Generator - NPN BJT Amplifier Analysis

I'm interested in creating a low voltage white noise generator by means of a zener diode, as detailed here: Zener & BJT Noise Generator. Specifically, I want to use the circuit here, in order to ...
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Zener Diode Selection for Relay

I am using a Zener diode along with a flyback diode with a relay in order to speed it up a bit. This works very well but I am currently using a rather over-sized zener from the inventory. For proper ...
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Protecting resistor value for zener diode in parallel with load

I want to select x as resistance for the protecting resistor (upper). The zener diode can hold up to 4A If I was guaranteed to have current through zener lower than 4A, I could consider its voltage ...
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Does the TL431 have a “dropout voltage” per se?

I want to get a stable 3V reference from a +3.3V ±5% supply (so it can go as low as 3.135V and as high as 3.465V.) I know the TL431 is a shunt/zener regulator, so doesn't really have a dropout ...
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Floating Voltage to Bias a P-Channel Mosfet without Exceeding Source-Gate Max Voltage

I'm not sure if this is what you'd call "floating voltage" or not. I'm lacking on some terminology so bear with me. Here's the circuit with explanation below: The premise of the circuit is this: I ...
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On a relay coil, why use an MOV instead of flyback diode?

I briefly encountered a designer who wished to use an MOV instead of a flyback diode with a relay coil. I don't know much about the application, but why would you want to do that? The only reason I ...
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Calculating the peak voltage of a zener diode output

I have a problem with this homework, I have to calculate the peak voltage of the output after stabilizing with a zener diode. My Input Voltage is Vin = 5V + 0.7Vsin (2pif*t) with f=10kHz My circuit ...
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Differences between TVS diode and Zener diodes, in diagrams and in practice?

I have been looking at circuit protection using TVS and Zener diodes. I have seen the following symbols used to represent TVS diodes in circuit diagrams: simulate this circuit – Schematic ...
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Using NPN BJT with a P Channel MOSFET to switch 3.3V to 24V

simulate this circuit – Schematic created using CircuitLab I have some 3.3V I/O on a PC Board. When an output is switched on, I need to switch the 3.3V output voltage with a +24VDC and provide ...
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MOSFET protection using zener diode

I have a question about this circuit, using Zener diode as a protection for mosfet. I've found some related topics but didn't found any circuit which uses the same configuration. Can anyone suggest ...
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How to calculate minimum zener current if it is not explicitly specified in the datasheet?

simulate this circuit – Schematic created using CircuitLab I'm going to use 1N4740A as a voltage reference in a similar way you see in the schematics above. In textbooks, a zener property ...
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Overvoltage protection with zener - How do you get a sharp knee clamp for analog input?

I'm working with an MCU that sees a 0-5V input range. I have a possibility where they may accidentally see 12V (user error). My problem is this analog input using a 5V Zener has a knee that isn't as ...
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Zener diode for solenoid

I am new in electronics and this is old subject but still. I started new Arduino project where I control 4 solenoid valves independently via Arduino 4 chanel 5 V Relay module. From the beginning I put ...
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What happens after a zener diode breaks down?

I've strapped a 6V zener diode across the 5V/GND rails of my circuit, and I want to know what will happen if my supply were to somehow fail pass 12V straight to the rest of my board. The zener will ...
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Using a Zener diode as voltage reference

I want to use a zener diode as a voltage reference to the the PIC18F2550, as the analog V+ reference. I am planning to use this zener diode, but I am not sure how to calculate its values. I am ...
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How to model a noisy Zener diode in LTSPICE?

I'm trying to simulate a white noise generator of the Zener diode style. I'm going with current amplification, rather than the more traditional voltage amplification just because. My problem is that ...
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How does a zener protect my microcontroller?

I'm connecting a 12V inductive limit switch for my 3d printer to a RAMPS controller (Arduino-based printer controller). The RAMPS board operates at 5V, and connecting the 12V signal from the limit ...
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Virtual GND resistor dividor vs zener diode

I was having a discussion with someone about using a virtual gnd for an opamp circuit. One way to provide the VCC/2 voltage is with a voltage divider made of two precision resistors (and a capacitor ...
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Protecting microcontroller from inductive loads

I'm working on a project where I will be controlling a variety of loads (relay, solenoid, motor) from an Arduino and I'd like to make sure I build in enough protection for the microcontroller and ...
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What use is a Zener diode's leakage current spec?

Consider this datasheet for a family of Zener diodes. All of the parts 3V and under have their leakage current rated as some current at 1V. I've seen this is multiple family datasheets, but it really ...
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Why do we need many complex voltage references when a zener can do the job

There is a huge variety of Zeners that exist. They have varying breakdown pd among other things. Why then do we need voltage references that are more complex and made up of many components?
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LED as Zener: is this a good way to lower the BOM cost?

I had an old AM radio board designed to operate with a 3V CR2032 coin cell. I want to revitalize this old junk with as few parts as possible and convert it into a USB-powered AM radio with a built-in ...
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LM335 doesn't seem to work

I'm relatively new to electronics, and I'm trying to make a thermometer using a LM335 temperature sensor. By reading the datasheet I thought it was simple, connect up 5V to a resister, then to the V+, ...
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BJT Circuit Problem [closed]

I am facing problem in solving such mixed circuits with bjt, diode, opamp and Zener diode. In the above problem 1.zener can have 3 states (ON, OFF, Reverse ON) 2.diode can have 2 (ON, OFF) 3.BJT ...
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Anti-wind up scheme in the implementation of PID controller

I want to implement designed PID controller. But I am facing the problem of how to limit the saturation limit in both positive and negative direction? I tried using zener diode, but I would like to ...
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Flip a Schmitt-Trigger when current flows through a Zener diode

I am trying to design a circuit using an intermitent power source (a bicycle hub generator), which is rectified and filtered, and regulated at 6,8V. Now I want to "detect" when the power source is ON ...
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Why is a resistor needed in zener protection circuit?

I have decided to add zener overvoltage protection to the I2C lines of my device. After some searching I have found that the most used circuit is: So my question is why do we need R3 and R4? If they ...
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Intrinsic Zener diode in MOSFET

I understand why some transistors have a built-in (normal) diode from drain to source, so that when the transistor turns off, back-emf can flow back up, specially important in inductive charges, but ...
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How improve temperature sensitivity of HP 721A DC Power Supply voltage reference?

I have a sentimental affection for my HP 721A DC Power Supply: http://hpmemoryproject.org/pict/wall_a/anim/721a_q90/viewer.htm Rugged, dependable, and roughly as old as I am, it is also pretty ...
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Zener diode BZX55C3V3 does not behave as Zener diode

I have bought a couple of BZX55C3V3 diodes to protect the ADC inputs of the microconroller but I noticed they all behave strange (and each one in a different way). This is a ST 3V3 diode (http://www-3....
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Understanding Zener diode datasheet

I am a beginner in electronics, and if you have a look at my profile, you'll understand that I'm completely confused in nomenclature of components. I recently downloaded a datasheet of a Zener diode ...
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1answer
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Choosing series resistors for zener diodes

I'm planning to clamp an AC 12V volt signal with two 8.2V zeners (1N5344B). After the zener couple the signal will be fed to an opAmp as in the figure below. Do I need a resistor (Rz in the figure) ...
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Transistor Series Regulator

I am in the 6th week in Navy school and we are on voltage regulators or circuits that have components that maintain a constant voltage output. I need an explanation on how to work out this problem ...
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1answer
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Hot air soldering without destroying ICs

I have designed a circuit board that has about 20 parts on it, including a surface mount LMV431 Adjustable Zener Shunt Regulator and MMBT2907 PNP transistor. It appears that every time I solder up a ...
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1answer
357 views

What function does this PCB circuitry serve?

Backside is metal disc with thermal paste between it and the metal mount to which it is screwed. Input is 6.75V 200mA. What function does the PCB circuitry serve? Is it stepping down the voltage or ...
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Voltage across Zener diode

Let's consider this simple circuit simulate this circuit – Schematic created using CircuitLab with $$V_S = 15 \ V$$ $$R_S = 500 \ \Omega$$ $$V_Z = 5.1 \ V$$ $$R_L = 1 \ k\Omega$$ It can be ...
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Op Amp as a simple switch

I want to build a little voltage switch that switches on a buzzer and a relay when a certain voltage is reached. Please have a look at the schematic. I use a trim potentiometer to set up the switch ...
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1answer
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Setting maximum opamp input voltage by zener diodes with respect to supply voltage

When I was about to implement a circuit with a 24V supply voltage I noticed that the comparator's inverting input in the part below receiving 24V with respect to ground when the input signal goes high....
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Output voltage at transistor of given figure

Can anyone give me hint of this question. I know this is homework question. I know correct answer is 10 v. But if I tried to solve it like this way: (1) Z1 and Z2 limit output 5 V and Z3 and Z4 ...
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Zener voltage selection for relay?

This question is similar to Zener Diode Selection for Relay but the focus is in how to select the voltage for optimum or near optimum release time. With the circuit below, how does one select the ...
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zener diodes, different voltages, and using a relay to control its opperation…will this work?

Ok so I am going to admit that I am an idiot when it comes to circuits. However, some advice would be appreciated with regard to my idea. I am trying to control two seperate circuits, each with ...