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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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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 ...
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1answer
91 views

MiniMELF Zener diode value [on hold]

I have a digital programmable relay. Unfortunately it burnt due to power short circuit or another reason. After open the circuit I have found two problems: The resistor acting as a fuse is burned. ...
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2answers
48 views

Zener temperature derating

Can someone explain what the Ta line on this zener diode temperature derating graph means please. The diode is an MCC SMBJ5338B 5.1V 5W zener. I understand the lead temperature (TL) line means ...
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2answers
78 views

How do I know that this BJT is in the saturation zone without having to simulate it?

I have to find the working zone of this BJT, for different values of P, by using a simulation software like Simulink. But I would like to know how to do it manually. The way I learned is sort of ...
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1answer
48 views

BJT Cascade Difference Amplifier Exercise

I need help with the exercise. The questions: Add or Design Components to have a current source I=2 mA at the picture. Draw equivalent small signal,low frequency model. Find Ai, Zo, Zi. If ...
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56 views

Use zenerdiode as voltage threshold circuit

My garage door opener has output terminals that output 10V as idle and 24V when the opener is running. I have the output connected to a 24V relay to control the lighting in the garage. My problem is ...
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1answer
82 views

How do I size a zener diode for use as a freewheel diode for a ZVS induction heater?

My electronics experience is "hobbyist" and I'm in some new territory with this question, so forgive me if this question turns out to have an easy answer or prove to be dumb. I have a basic ZVS ...
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1answer
54 views

Input circuit - Current and Voltage calculation

I have Input voltage : 6.5V Zener breakdown is 3.6V. Does the 3.9K and 4.7k ohm resistor acts as a voltage divider? or what purpose does the 4.7k ohm serve? And can someone help me how to ...
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51 views

Pulldown for zener voltage shifter

I would like to know whether R24 has been correctly applied to pulldown the EN pin when none of the diodes are switched on. The idea here is that voltages higher than 3.3V may be applied from any of ...
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1answer
89 views

Zener diode question in simple LED circuit with anti-flicker for model railroad

I am a total novice when it comes to electronics. I had a simple circuits class 30 years ago as a software undergrad. I've designed a simple LED lighting circuit for N-scale model railroad, to be ...
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4answers
90 views

Voltage error when connecting a zener diode

I am working on a project where i need to measure the battery voltage and send the measurement to a uC, which is powered by 3.3V. The voltage divider is projected as shown before: As input we have ...
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2answers
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Can a zener diode with a higher power dissipation be used in place of the original one in an audio amplifier?

Following my Marantz PM-68 repair question, I would like to change a faulty zener diode used in the amplification stage. I don't really understand the purpose of this diode but I guess it's used for ...
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2answers
53 views

Relay Driver with 24VDC Relay… Zener diode?

I am part of a physics project group, and we are trying to design a relay driver. Our Relay is rated at 24VDC (it is a Tyco Electronics 1432826-1). What zener diode (or regular diode if that would ...
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3answers
134 views

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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0answers
38 views

using a TVS in place of a zenner diode

I have read somewhere that a TVS is nothing else than a robust Zener diode. My application requires using 300V zener diodes (that may exist but do not pop up so easily), but TVS at 300V are very ...
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1answer
47 views

Disambiguation of Anode and Cathode Terms in Diodes

In a regular silicon junction diode the positive side is the anode an the negative the cathode. But when someone uses a Zener diode that operates in reverse bias there is a problem with what ...
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1answer
58 views

Over voltage protection for a buck controller 24V in. 4-5V out

Please see Image below, if the output votlage here is 4-5V with current out 3A-15A(depending on LOAD). Could I stick a Zener diode to clamp any over voltages to protect the load from over voltages? ...
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1answer
96 views

zener diode circuit analysis

I'm studying Zener example and it doesn't make sense to me: the Example - with solution in the above picture i can see that input is 26.4V and Zener voltage 14.56V. when load 1k connected. but in ...
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2answers
74 views

Can Zener or Schottky diodes be used as a substitute for varicap diodes in tuning a VCO?

In particular, this would be a fairly low frequency VCO with a frequency range of 10 Hz to 20 kHz. I'm thinking of the configuration with the T-junction that has 2 opposite facing, reversed biased ...
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1answer
73 views

Use zener diode as regular diode

I have a circuit that uses regular diodes, and I only have zener diodes in hand. As I understand, zener will conduct after a certain voltage in reverse, so all I have to do, is pick a voltage that is ...
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1answer
124 views

Zener diode parallel to RC circuit

In the left hand side part there is a diode in series to parallel RC network. And in the right hand side there is a zener diode in parallel with series RC network. How do these sub circuits operate? ...
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2answers
77 views

Load resistance in voltage regulator

I want to find the minimum resistance \$R_L\$ so as to maintain \$V_z\$(voltage of the zener corresponding to the minimum current \$I_{z_0}\$) across the same resistor \$R_L\$. simulate this circuit &...
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3answers
76 views

Over-voltage protection system for a 7 - 20 A Load with 4 - 5.5 V output from PSU

The power supply used on the product, is a DC-DC buck controller 24 V in (3 - 5.5 V out). I need some suggestions to help protect a load (LED Display) which draws roughly 5 - 15 A the power supply on ...
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2answers
45 views

What could be the output current rating of the following shunt regulator?

I am trying to solve the 2013 paper set by ISRO for electrical engineers. I wanted to verify if my answer to Question no 18 is correct. So \$I_L\$ is being drawn out of the circuit shown. Since the ...
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1answer
121 views

Using a zener diode to limit current to an IC for various input voltages

I'm designing a board based on TI's DRV110 solenoid driver. The datasheet explain that: "The DRV110 is able to regulate \$V_{IN}\$ voltage from a higher external supply voltage, \$V_S\$, by an ...
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3answers
120 views

Battery indicator Circuit

Many of battery indicator circuits are designed using 2 or more leds like in the image above but how to design a simple battery indicator circuit using only RGB LED and transistor for 12v battery ...
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1answer
47 views

What is the purpose of a schottky/zener couple on an isolated flyback topology?

This isolated flyback topology has been generated by TI's webench. It's a classic schematics with a feedback going through an optoisolator. There are, however, two diodes connecting the switching ...
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1answer
92 views

Mosfet Gate-Source Zener [closed]

I want to confirm this circuit is going to work and ask how to calculate the zener voltage. The load is going to be driven by 30 volts, and the gate voltage is the same 30v, through an optocoupler.
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2answers
136 views

What is the purpose of these diodes in this opto isolator circuit?

I came across this circuit which I think is to isolate a high voltage signal to a safe level for GPIO of a 3.3V micro controller. My question is that how on earth this circuit works...There are 2 ...
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1answer
138 views

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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1answer
122 views

Calculating the minimum and maximum \$R_{load}\$ for a zener voltage regulator

So, I have a generic zener voltage regulator with \$R_{s}=650Ω\$, \$V_{in}=15V\$, I'm using the zener BZX55C8V2 (datasheet). From the datasheet the test current is \$5 mA\$ and the maximum zener ...
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1answer
56 views

Wide voltage range comparator (with zener diode)

i need to switch the transitor (Vce minimal) when input voltage (0 - 18V) is greater than 6.3V. To achieve sharp edge I use a zener diode D1. However, I also need a protect transistor base, so I use a ...
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0answers
87 views

Find voltage across load resistor

Here the zener voltage of the zener diode is 3.3V and base to emitter voltage drop is 0.7V. What is the voltage across the load resistor and how to find it?
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92 views

Zener diode equation proof (chacteristic curve)

I'm trying to prove this equation(at least I think that's the correct one): which produces this graph: I can prove the one that describes the PN diode but I am not sure what I should do differenly ...
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1answer
98 views

Reduce Noise Added With Zener Clipper

I'm working on a hobby Arduino project to create an audio visualizer using an LED strip. I'm using the MSGEQ7 to separate the signal into 7 bands, then send it to a Wemos D1 Mini. I started by ...
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2answers
72 views

Calculating time-constant with z-Diodes

I'm a student in Computer Sciences and am currently preparing myself for an Exam in Electronics. I came across this Exercise: (U_0(t) = 10V), u(0) = 0V) I don't have any solutions for the exercise, ...
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3answers
80 views

MOSFET for revrerse voltage protection

I have used the following circuit to for the purpose of reverse voltage protection. But, I am a little bit confuse about the working of the zener diode in combination of the 100k resistor in this ...
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1answer
213 views

help understanding this reverse polarity protection circuit

Going through LT4363 evaluation kit DC2062A-B (schematic here), I came across a reverse protection circuitry that protects downstream components from reverse transients and reverse DC voltage: In ...
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3answers
132 views

Power of the Zener diode

In this circuit there are several things required like the inductor and diode current, and the average power of the inductor, but what does really puzzle me is how can calculate the zener average ...
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1answer
109 views

Noise generator with LM318

I want to build a noise generator from a Zener diode. I designed the above circuit. The noisy voltage from the diode is filtered via a high-pass filter and input into a 92x gain non-inverting ...
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1answer
39 views

Powering a low current device from a mosfet N

I have a question regarding a circuit providing low current capacity voltage for device powering, that goes down from a lot higher voltage: How does it exactly work? I understand that the Q1 gate is ...
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2answers
52 views

P-Mos switch high side

I'm trying to switch P-Mos given that: Vcc > Vgs max Enable_output is 0V or 3V I'm switching both GND and VCC on purpose. 4. 8.4VR at 2uA ! The questions: When Q2 is off, what is Vgs at Qsp1? Is ...
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7answers
489 views

Calculating the voltage drop of two Zener diodes in series? (reverse conducting)

I'm building a circuit powered from a 12V 55mAh (A23 battery). Needless to say that power consumption is a primary concern. The circuit is an ATtiny85 which is driving 13 LED's (in 5 groups). I ...
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1answer
121 views

How to find voltage on zener diode while there is a current source

simulate this circuit – Schematic created using CircuitLab I'm confused about whether zener is on or off due to not being able to know voltage on V0. I tried to find by applying KCL & KVL, ...
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5answers
104 views

Does a transistor work by connecting the collector to emitter? If so, why do transistor regulators work?

I am wondering why a transistor, such as one used in this Zener diode + Transistor regulator , has the output controlled by the base voltage rather than the collector. My textbook (which has this ...
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1answer
89 views

How does this Current Comparator Circuit Work?

I have a quick couple of questions about this circuit: The schottky diodes are obviously for minimizing slew delay but how exactly do they do this? If the non inverting input is tied to ground and ...
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1answer
62 views

PSPICE graphs work separately for subcircuits, wrong when combined?

I'm working on a pulse generation circuit that will be used to drive an ultrasonic transducer. The following circuit is giving an unexpected output. It might look complicated, but really it can be ...
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1answer
57 views

High side driver internal design

I have a question about the high side driver VN7016AJ for automotive applications, during ISO pulse1 -150 V will be applied at its VCC pin, I found from the User manual (UM1922) that when -150 V is ...
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1answer
187 views

What is a typical reverse recovery time for a zener diode, or is reverse recovery time not applicable to zener diodes?

A little background.. I'm trying to understand how zener diodes respond to high voltage transients. I stumbled across discussions of reverse recovery time and I'm curious how it applies specifically ...
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3answers
281 views

How can I create voltmeter with Zener diodes?

simulate this circuit – Schematic created using CircuitLab 5 LEDS One LED is to remain always on when current is passed through. One LED will turn on when voltage is between 50 to 90 volts. ...