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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 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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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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88 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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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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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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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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113 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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111 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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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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54 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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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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114 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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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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50 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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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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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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88 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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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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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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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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120 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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89 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
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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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44 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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351 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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110 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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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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75 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
61 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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50 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
140 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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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. ...
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107 views

High voltage to low voltage in ps/nanosecond time (Zener/opamp?)

So I have a signal that goes from 0 to ~800volts in 30ns. I would like to use this signal to trigger a camera (input impedance of 50ohm) which takes a max of 10 volts and requires the rise time to be ...
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196 views

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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48 views

Zener Shunt Regulator Question

I want an alternative low component, transformerless power supply for low power DC projects, I have used Shunt Regulators in the past but never with AC. Below I have proposed a AC to DC shunt type ...
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Confusions with placing and sizing the flyback diode, TVS and Zener

I have couple of questions regarding the location of flyback diode and sizing and locating the Zener and TVS diodes. For example below at the far end there is a magnetic relay which is controlled by a ...
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108 views

Using a zener diode and a bjt to regulate voltage received by a controller

Okay, here goes… I’m trying to create a circuit that will prevent low conductance (from rain water exposure) which occasionally shorts a particular switch, from triggering a controller input that the ...
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How can I compare a TVS diode with a varistor?

For a 120Vac line protection element, comparing this TVS diode: With this varistor: The immediate differences I see are: The varistor is marginally cheaper The varistor specifies a maximum working ...
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3.3v Zener Diode Shunt Voltage Regulator giving a 4.3v output

We are trying to use a zener diode shunt circuit to develop a voltage regulator. Our input voltage is 5v. Our desired output voltage is ...
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203 views

Zener diode at inverter op amp's output

I would like to know what would be the effect of placing a Zener diode between the op amp's output and the actual output of the circuit like shown in the schematic. The Zener should be of 5 V. ...
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Protecting against over voltage but with minimum leakage current

I have a circuit where I sense an input which is a voltage divider with resistor. Since the voltage divider needs to have high impedance, the current flowing through is in the range of 10's of uA. I ...
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1answer
102 views

Why is Zener reverse based on relay circuit?

In a common relay circuit a zener diode, or other diode, is used to shunt the spiked that the relay could cause. Now, why is the zener's cathode connected to the battery (or other source)'s positive ...
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87 views

Using a voltage divider with buried zener voltage reference

My plan in the below circuit was to use a voltage divider from a Max6225 2.5Vref, to get 2V and 1V from it in order to use the full 16bit bipolar scale of the ADS1115s, but I'm getting strange ...
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569 views

Create a blinking LED circuit with a z-diode and a capacitor

I was searching for the most simple LED flashing circuit. On a webpage (http://cappels.org/dproj/simplest_LED_flasher/Simplest_LED_Flasher_Circuit.html) I found the following circuit with a transistor ...
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1answer
86 views

Schematic for input protection with NMOS? Does this really work?

I was reading an old schematic and found this and sketched it up; (see box in image "Some kind of protection") The closest thing to this schematic that I've been able to find, that could have briefly ...
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262 views

What is a simple voltage limiting circuit?

I am searching for a neat solution for an input voltage limiting circuit. Situation: I have a circuit with an input voltage range from 6 V to 20 V at 3 A peak (the load), however my source can be ...
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Lead acid battery charging current dosent become zero

Here I am charging a 6V 4.5Ah lead acid battery by using a 8V-10V LM317 input supply for the circuit. I'm using the BD139 transistor to cut off and a 6.8V zener diode. As the battery voltage reaches ...
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59 views

High Side Driver IC - Application Information

I have a question regarding VN5025AJ-E: High side driver IC. Datasheet link - https://www.st.com/resource/en/datasheet/vn5025aj-e.pdf In the figure you can see the application schematic. In the ...
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104 views

1N4728 Zener behavior

Here I have the image of a signal in the output of U2, and the output is shown in green in the graph(sorry for the poor quality). Highest value = 3.3V, Lowest value = 0V, sine wave, 60 Hz. Now I have ...
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What's the cheapest way to make a dithered-input ADC?

I know that some of these PICs have ADCs built in, and I may want to use that. I am wondering if there is a way I can effectively dither the input to a low-bit (like 8 bits) ADC with the fewest parts ...