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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54 views

Overvoltage protection when going from 24V AC to 3.3V DC

I'm trying to wrap my head around transient voltage protection and how to implement it when also trying to rectify a AC source to DC then step it down to 3.3V for a microcontroller. I understand that ...
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Is this a correct way to do a low voltage cutoff for motorcycle use? (Zener diode + relay)

I want to design an electrical component that I would connect to my motorcycle battery. As I do not want it to fully discharge my battery and I want it to run only when my motorcycle alternator is &...
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How can I determine the Vo?

I think both of the Zener diodes in reverse bias and I think the output will be 4 V. Am I right? If I am wrong please explain the answer.
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Circuit problem with Zener diode acting like an open circuit due to voltage being less than breakdown voltage

Find the current through Zener diode? - JEE mains 2019 In the solution, initially, the same circuit without the Zener diode was taken and it was found that equivalent resistance is given as 1250 ...
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TVS/Bidirectional Zener for N-MOSFET Gate Protection

I am using a MOSFET to read a square wave, which usually ranges between -1 and 16 V. However, on occasion, the signal can reach values of -30 to 45 V. My current setup uses a Zener-protected STN3N45K3 ...
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Protection circuit with polyfuse and zener

I'm designing a protection circuit with polyfuse and zener for DC 5v input. I have try it fisically but the polyfuse never trigger because the zener burns before when I plug 6-12V to the input. My ...
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Zener diode - Zener voltage vs reverse voltage specification

This may be a very simple question with a straight-forward answer, but I cannot get a clear answer on this. Consider the following Zener diode. The table on page 2 lists a column for Zener voltage \$...
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102 views

Rectified 230VAC to 24VDC

I am building a simple motor control application, driving a series wound motor that runs on rectified 230VAC. Originally, it was controlled by a pendant switch connected to a 7 pin connector. The idea ...
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Zener Diodes: How are different voltage drops achieved

How do semiconductor makers make zener diodes with a fairly wide range of voltage drops? In particular I'm curious how they get small increments - 3.3V, 3.6V 3.9V, 4.2V, 4.8V etc as I thought the ...
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Tunnel diodes Zener breakdown

Do tunnel diodes exhibit Zener breakdown? Since tunnel diodes are more doped than Zener diodes they should, but I am unsure.
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How much voltage before Zener diode will be physically damaged?

I have this 1N4742 Zener diode which is specified to have 12V nominal Zener voltage. What will happen when I apply a 20V as a source voltage for circuit containing the mentioned Zener diode?
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Buck converter without oscillator?

I apologise for the attached picture, I just made sure everything is readable so you can assist. So I'm wondering if this is a logical idea, if 12 volts is supplied, to the circuit, as the capacitor ...
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Zener diode simulation issue

I have this simulation issue and I don't know how to solve it: The Zener current is smaller than the breakdown current yet the Zener diode still acts like a voltage regulator. Any help? Shouldn't the ...
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Understanding high-speed Improvements to discrete BJT multivibrator

What exactly are the Zeners doing in this circuit? I've been trying to improve my understanding of BJT's, by trying to 'improve' the classic astable multivibrator. In an effort to 'sharpen' the ...
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Need help to identify this diode

Need help identifying this SMD component which is shorted. I suspect it is a Zener diode. I have searched the markings ad nauseam but could not find an answer. The length is 5mm, so I believe it is a ...
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Help identify smd component

Im trying to repair a diagnostic interface, I've got a burnt chip and cant find any board data. Multimeter: diode mode in one direction reading : 1380, in other way 820 test in resistance ( 2000 ohm ...
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Level-shifting with limited ways to change the board

I have this circuit: simulate this circuit – Schematic created using CircuitLab Where: U1 is an MCU powered at 3.3V OUT is a GPIO the dashed box represents an external hardware that I cannot ...
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How do I create a secure clamping circuit?

Clamping is good for transients, e.g voltage peaks. But two issues with clamping is that if you have a linear voltage regulator attached to 3.3v and 3.3v is the voltage regulator output, then that ...
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2.4V Zener diode regulator not clamping

I am trying to get a toggleable 2.0 to 2.6 ish voltage reference that can supply up to 45 mA. I simulated the below circuit and found this to be acceptable. However upon building the circuit, I found ...
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How do I protect a unipolar ADC input against a bipolar signal?

I am designing a circuit that should convert a unipolar differential audio signal using an ADC. The signal varies between 200mV - 28V peak to peak and I'm planning to use the TI PMC6020 ADC that ...
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129 views

Zener diode as temperature sensor

I am trying to measure the temperature of a battery pack using Zener diodes. I want to use Energus's Tiny BMS 30A. In their battery modules they use Zener diodes to measure the temperature of the pack ...
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Identifying diodes types and values

I need to know the type and value of these two diodes, in order to buy two equivalent ones. Can you help me to find it out please? The diode with the yellow stripe has no markings, while the other one ...
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Can I use a Zener diode in place of a 3.3V voltage regulator to power an nRF24L01?

The nRF24L01 operates at a voltage range of 1.9 – 3.6V. I have a power supply of 6V. I need to regulate to 3.3V. I used an LD33V (3.3V regulator), but I need other solution, so I decided to use a 3.3V ...
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Why does this Zener diode circuit not produce the Zener voltage?

Why does the measured voltage at the op-amp input equal 2.02V? simulate this circuit – Schematic created using CircuitLab
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Maintaining Zener voltage @ 0.9 of Zener voltage

I have a strange question (at least to me.) Suppose I have a Zener diode, to be very specific, 1N5234B. It has a Vz = 6.2V, Izk = 0.25mA, Iz max = 80.645mA. Suppose I have want that Zener to maintain ...
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line regulation factor with 2 zener diodes

i want to calculate the line regulation factor of this circuit You can check below my work. is it right or not ? Correct me if i'm wrong Can we consider that Z1 has a similar function as the ...
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how to choose diode for PWM of high amperage solenoid?

I'm making a pulseable solenoid circuit via PWM at around 20 hz. THe solenoid is a heavy industrial type that pulls a whopping 18 amps. My snubber circuit gets hot and burns up as the current is too ...
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Can I use a back to back Zener as a flyback diode for an AC coil?

I am using the below AC electromagnet to switch on/off a pneumatic system. (It is a pneumatic actuator. I think that is what it is called.) The issue is, when I turn off (disconnect the switch) the ...
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Minimum power rating of zener diode

The minimum power rating of a zener diode is defined as the maximum power that can be dissipated through it in a given circuit. Why do we define it in the opposite way? Minimum power rating should be ...
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A circuit that can clip a high voltage/ low current signal input to an Esp32?

I have a program for an Esp32 development board which detects the ignition spark from an engine and converts the frequency of the ignition to an engine RPM reading. The high voltage input peaks at ...
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Which is better for an adjustable stable reference voltage output?

I have two methods of achieving this and am trying to decide which one will be a better option for a stable output. The supply voltage is a linear regulator output, so it is pretty much constant. ...
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Zener diodes for JTAG interface

For my new PCB, I want to use a 7-series XILINX FPGA. I was a little bit unsure of the JTAG interface so I looked up some schematics of XILINX evaluation boards. I found the Arty S7 50 schematic. The ...
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Active voltage limit circuit

In my application there is a signal from 0-10V. The signal gets into 4 different OPAMPs with different gains which are supplied from +- 5V. I would like to limit the input voltage to the OPAMP to 0-2....
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Explaining the positive and negative regions of the output waveform in a circuit involving a Zener diode

I am trying to find the explanation for the output waveform at Vo of the circuit below: The output voltage is as follows: Perhaps the explanation why the form is as such during the + cycle is ...
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Voltage stability factor of voltage regulation circuits

Here a shunt voltage regulator circuit with two Zener diodes. One Zener diode Z gives the reference voltage at the comparator given by T1 for the feedback signal out Ra-Rb potentiometer. I can't ...
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What is the main difference between a zener diode and normal diode?

I have read that zener diodes at some certain voltage let current flow through itself when it's reverse biased, but why can't the same happen in normal diodes? What is the use of zener diode?
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Can we make a transformerless 220V to 12V converter without a Zener doide?

I saw many circuits have a Zener diode, but a guy from Youtube lighted up a 12V LED without a 12V Zener diode in the cicuit. How is that?
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Capacitive dropper power supply for LED - zener/decoupling capacitor?

Let's say you have a standard capacitive dropper power supply like the following (from Wikipedia): I understand that these work well for driving LEDs since they act like a constant current source. I ...
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1answer
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ESD array power and protect from same source

I am working on incorporating ESD protection for flash circuitry on ESP32 custom PCB board, and after initial research, ordered an ESD Array (CM1293A-04SO) from digikey with datasheet here Attached in ...
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How does this voltage-reference circuit works [duplicate]

I have been trying to understand how this circuit works for the past few hours, it is supposed to be a voltage reference circuit that uses a zener diode, I am supposed to derive an expression for Vout ...
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191 views

PNP transistor constant current source

I would like to know if it is necessary to add a base resistor to the Q1 transistor in the below schematic? The complete schematic: https://ibb.co/kc5QkSC
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Need help identifying SOD-123 packaged Zener diode with WG G0 marking

I'm looking for help identifying a SOD-123 packaged Zener diode with WG G0 marking like the one in the photo. The board has quite a few of these with one of them completely burnt. The closest I've ...
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Zener Diode Current Problem

In the diagram below, ignore everything except for Dz and Rvdd. Dz's job is to protect the VDD pin in the event that the voltage input into that pin goes over 20V. Rvdd's job is to limit the current ...
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If I want to constrain a signal to +- 5 V, what arrangement and rating of zener will I need?

I have set up a circuit with two zener diodes head-to-head with a resistor upstream, to limit a circuit signal voltage to +- 5V. On measurement, the 0.7 V of one zener appears to be summing with the 5....
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Overvoltage protection for DC controlled Device

i've designed this schematic using a simple buck converter (LM2596) for my board that powers up some leds and board peripherals. The board will work at 5V with maximum current draw of 2.5A. Now, as ...
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Issues with simple NiCd battery charger circuit

Inspired by this circuit, I'm trying the following one for charging 2 NiCd batteries: simulate this circuit – Schematic created using CircuitLab There is a current limiter part, with a red LED (...
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Voltage drop regulator 12 V to 5 V, voltage reference with zener diodes

I try to build a low voltage drop regulator to bring the voltage down from 12 V to 5 V (ignore everything right of the capacitor C3). I have a 12 V voltage supply and I want to feed my OpAmp with a ...
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79 views

Digitally variable zener diode reference

I'm trying to use a digital signal (3.3V or 0V) to set a voltage reference for a comparator (4.7V and 6V.) I've come up with the circuit below but it doesn't seem to be very precise and I can't seem ...
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Two led voltage indicator

I need a schematic of voltage indicator with two NPN transistors and two Zener diodes. When the input is 9V one led is lighting, the other when the input is 12V. This is my progress, but I'm not sure ...
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Calculating at which source voltage, Zener regulation begins

I've been trying to understand how to get to the voltage at the source with which the Zener starts limiting the voltage. Circuit and graph in the end. The diode model used was from Motorola. The ...

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