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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TSM104W Voltage Reference

Hi I am trying to design with the TSM104W, which is a 4 package rail-to-rail OpAmps, with a built in voltage reference. This is the package pinout: I see that the four Op-Amps are supplied through ...
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25 views

Trying to understand how they got equation for Vzo

this might seem like an easy question but I'm still new to circuits and I'm trying to understand how they got the equation for voltage. They have the solution as 6.8=Vzo+5m(20), but when I looked at ...
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Relationship between Zener diode voltage and knee voltage in forward bias? Also the resistance in forward bias

Can somebody please help me establish a relationship between Zener diode voltage and knee voltage in forward bias? That is something where I could not find anywhere.
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How to calculate the power rating of zener diode for flyback protection?

I'm trying to calculate the power rating for the zener diode I'm using on my circuit for flyback protection. For example, if a flyback event occurs, the cathode of the zener diode is having a 30V ...
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36 views

Power zener with mosfet + zener

I have two solar panels in series giving ~106 volts when open circuit and around 4 Amps when loaded. My mppt controller could accept 150v on the input, but it blew up when the battery was ...
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38 views

Overvoltage protection Piezo Harvester

I have a piezo harvester, capable of creating spikes of 50+Volts. My harvesting circuit which will be connected to the harvester output, has a maximum rating of 20Volts. Therefore I need some kind of ...
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71 views

Why are zener diodes not used for capacitor balancing?

Why are zener diodes not used in parallel with electrolytic capacitors for balancing purposes? Large electrolytic caps generally have a large leakage current (~3mA) which results in large losses in a ...
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51 views

zener diode with op amp

hei Guys, im not sure about but i think is the input Vin<0 the Output Voltage will remain 0,7 and when the input higher than Vin>3 the output Voltage will stay -3 .... and in case we remove the ...
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22 views

Calculating load regulation in this zener diode circuit

I'm trying to find a good method to calculate the following two values of the circuit below: $$\bigg(\frac{dV_L}{dV_S}\bigg)_{i_L=constant}=?$$ $$\bigg(\frac{dV_L}{di_L}\bigg)_{V_s=constant}=?\\ \\$$ ...
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136 views

Triangle wave input with Zener and diode

I've found a problem posted as a question in one of the past exam periods. I've tried reviewing it with my peers, and we all get to different results, which makes me think my understanding is ...
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Current limiter low voltage drop

I'm trying to understand the function of the constant current regulator CCR and the zener diode 1N5338. I do have more questions but these two components is probably a good start. I understand that a ...
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Can I use any digital component to avoid 7805 killing my microcontroller directly when its ground is disconnected (hence 12v goes to uC directly)?

My idea is to have an intermediate cheap component that will blow-up before my uC if the voltage goes above 5v from 7805 (or even some fuse, but I am not sure if a fuse will blow-up with over-voltage ...
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50 views

BJT PNP AND ZENER DIODE Circuit Analysis Problem

I am facing problem in solving such mixed circuits with PNP bjt,and Zener diode. I solving a problem but my results are different to the solution. Could you tell me if my procedure is correct? I don’...
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Why do my all Atmega328P chips stop responding suddenly in a 12v circuit with Zener diode?

I have noticed this strange thing where my atmega328p stops working and when checked through Arduino IDE or AvrdudeSS or ProgISP, they show programmer not in sync, rc=-1 initialization error (while ...
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55 views

Series Limiting Resistor?

I have used a 3.3v and a 4.7v zener diode and please what will be the amount of resistance to operate them without any issues. The test current for 3.3v is 76mA and for 4.7v is 53mA.
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31 views

What is the output in Figure 3-19(a) if the input voltage is increased to a peak value of 20 v?

Will it be the same as if the input voltage is still 10 V? Or the zener diodes will breakdown (get damaged)?
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Zener diode in parallel with both the input terminals and the output terminals

"There is a zener diode in parallel with both the input terminals and the output terminals. Combined with the fuse these should help in reverse polarity situations (it should blow the fuse before ...
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74 views

How can I make a simple circuit to output only after a min input voltage is exceeded?

Here's my problem.... I am setting up a camera system on a motor coach that is designed to trigger separate cameras when blinkers or backup is engaged. the problem I'm having is the only accessible ...
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4answers
59 views

Reverse polarity protection on 5-12V input and output

Can someone help me with reverse polarity protection on 5-12V input and output using a using a P-Channel MOSFET? How can I calculate which MOSFET, resistor, zener diode I have to use? I use a 5V 10A ...
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80 views

AC to DC conversion: is this an appropriate implementation?

I understand that a 20v AC converter supplies 20V RMS AC. I wish to convert this to 20v DC and so have drawn up a schematic for this which includes: the AC to DC conversion, regulation, smoothing, and ...
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Voltage Regulation: How do I work out the required resistance?

Outline: I have available a 12 V power supply rated at 50 W maximum. I need to power a device which takes 4.5 V at a maximum of 1.5 A. I plan to use a Zener/transistor schematic. Question: Given the ...
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What are the disadvantages of using a Zener diode over a linear voltage regulator?

I wonder why a Zener diode is worse than linear voltage regulator. Some of the posts online mentioned that because of the power dissipating problem. Zener diodes keep consuming a large amount of ...
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Can someone explain this high-speed P-channel MOSFET drive circuitry?

I found this circuit in an application note on P-Channel Power MOSFETS. The note explains that modern technology has made it possible for P-Channel MOSFETS to approach N-Channel performance in power ...
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29 views

Voltage Regulation for a high frequency signal - Arduino Input

I'm trying to build a digital tachometer for my motorcycle using an Arduino nano. I have researched a lot on how to reduce the 12 volts from tach signal to 5 volts to be read by the arduino. One post ...
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How to solve the (b) circuit?

In circuit b there is a Zener, LED and transistor the voltage of base I assume is 12 V - 6.2 V = 5.8 V so I guess Ve is Vb - Vbe = 5.8 V - 0.7 V = 5.1 V but I can't guess the current which is passing ...
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141 views

ADC protection for PIC microchip

I need to protect the ADC pin of my PIC18F27K40 from over-voltage and reverse voltage for a 0-10V input measurement. After searching the web, I found the following solution : When testing with ...
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63 views

Why doesn't the voltage of the load fluctuate in a Zener Diode circuit?

I'm very new to this field so sorry for this silly question. What I've learnt is that when any number of devices are connected in parallel (and none in series with the battery) with the battery, the ...
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Can I extend the allowed Vin range of a voltage detector IC with a simple zener shunt regulator?

I'm trying to solve a particular corner case in the behaviour of a system I designed. The issue can be boiled down to this: I don't want a particular LDO to operate if it's input voltage is below 4V (...
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Can you help me improve this circuit design?

I'm a electronic noobie and for a school project I need to design a circuit that will then be connected to a micro controller. The aim of the project is to build a sniffer to decode a particular ...
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166 views

How does this circuit work (OpenTherm)?

I am trying to understand how this data interface works. It's supposed to: translate (read) "OT" current difference into logical OUT (<10mA = 0, >17mA = ...
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1answer
22 views

Can I edit an incremental resistance of zener diode in PSPICE?

It seems like breakdown voltage and current of zener diode model in PSPICE can be edited like the screenshot I've uploaded(BV, IBV). But I want to change the incremental resistance of diode(Rz). Is ...
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60 views

What is the explanation for the shape of the Zener avalanche effect?

The following diagram is a trace of a Zener diode in avalanche. I can understand the explanations behind shapes A - D, but what causes shape E? A is the accumulating charge within the junction's ...
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41 views

eMMC to SD card adapter

I am trying to connect the eMMC of the Firestick to a micro SD. The output voltage from the SD card to eMMC is 3.3 V but I need 1.8 V. Could I use a resistor and 1.8 V zener diode for this or am I way ...
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How to estimate the series resistance for this zener regulation?

There is a variable load that draws current between 1mA up to 1.5A. I want to supply the load with almost constant 4.2V(precision not improtant). If I only have 5V supply I thought I can perform the ...
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78 views

Ringing seen when a zener diode is used with series diode as a snubber

I am trying to simulate the snubber circuit as given in "A zener with series diode"? there is some ringing seen at ouput. Here is LT spice ckt: Simulation result shows some ringing at ...
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76 views

BJT with collector base or base emitter shorted

People have been using BJTs in various configurations with either of the junctions shorted. The following queries persist for these configurations. Links to previous questions are added 1)Base ...
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Why doesn't my multimeter show the correct Zener reverse voltage?

I have a 3.3V Zener diode, brand new from a reputable source. When I set my Fluke 101 multimeter to diode test mode, and put the black lead next to the dark bar on the diode and red on opposite side, ...
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58 views

Question regarding shunt regualtor using zener diode

simulate this circuit – Schematic created using CircuitLab I am not able to get proper 3.3volt output at the output capacitor. Since 3.3 volt zener diode have been used, there is a drop in the ...
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104 views

Why Zener diode doesn't fire at specified voltage?

I have the following schematic, which would be used as a over-voltage and reverse polarity protection: simulate this circuit – Schematic created using CircuitLab Both D1 and D2 are rated at ...
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98 views

Designing a diode waveform shaping circuit resulting in specific transfer function

Below is the circuit I built, yet the solution has the resistor as a load resistor instead of as a current limiting resistor. I am wondering if this circuit will output this transfer function.
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Zener diode conduction

Why doesn't the zener diode conduct even while the battery is being charged at a higher voltage than 6.8v? I assume that to charge a battery the charging voltage has to be more than the batteries ...
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1answer
886 views

LTSpice Zener diode bug?

I'm trying to design a circuit using a zener diode but am having issues getting it to work right. This circuit works fine and show Vout = 6.198V. However, if I swap their positions - Here, Vout = ...
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38 views

Slight drop in voltage regulator circuit

Below is a voltage regulator circuit for which I measured Vo and Io over a range of load resistance values. Why is there a slight drop in Vo when Io is increased, does it have something to do with the ...
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1answer
105 views

What is the purpose of a resistor in series with a potentiometer?

I assume the 100 Ohm resistor is in series with the potentiometer so that the circuit is not shorted if the potentiometer has a value of 0 ohms, however, I know that will not affect the circuit ...
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389 views

Limiting sensor input voltage without biasing measurement

I need to measure precise voltage in the range from 0.375 volt to 10.1 volts from a source with 100ohm impedance. Maximum voltage however, may be well above 10.1V, so I need to be sure I do not ...
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221 views

Reverse-polarity protection P-channel MOSFET

There are many ways one can build a reverse-polarity protection circuit. Using diodes, Shottky diodes, n-MOS in the return path and using a P-channel MOSFET on the positive side of the circuit. My ...
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41 views

What is the value of the node voltage, V1?

The value of the Vz (voltage across the Zener-diode) is 4V. There is also a current flowing against the diode. We know that when a diode is in the zener region, Vd = -Vz. I tried a simple KVL and got ...
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154 views

Capacitor in parallel with relay coil backfires on contacts

I've got a smoothing capacitor(2,2uF) C1 in parallel with relay coils inside a fullwave diode bridge. When the circuit is closed through contacts in pre-relay RLY1 it first gives me, almost everytime ...
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47 views

Over voltage protection without shorting the Output to GND during Over voltage

Here is the circuit diagram i am referring. Vin_12v_ext - Max 12V; Batt_V = max 5.4V; Vin_ext_12v_gen is either Vin_12v_ext or batt_v; 5v_reg - is either generated by an on board regulator or ...
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3answers
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Input Protection Diodes Functioning with Circuit Breaker?

I was wondering if I was correct in assuming these diodes were being used for ESD protection on the input of a power circuit. I'm a little bit confused what the point of the diodes are when there's a ...

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