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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Zener Regulator supply to IC

In below Design , working ok with Vcc was 5V, but due to some modification I have only 15V power supply available to use this circuit. So i change as per 15V requirement ( see below image), Pin 1 is ...
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What is the upper frequency of a zener used for transient voltage suppression?

I have just answered a question here, and it has spurred me to ask a question: How fast will this type of protection work? Would it work with, say, a 500kHz signal? And is there an easy way to work ...
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Low voltage cutoff circuit not working

I've spent the past 10 hours trying to figure out why my low voltage cutoff circuit won't work, and I'm at the point where I feel like I need to ask for help. The idea is to slap this circuit in ...
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Noise Model for Zener Diodes

I am trying to design a noise source using discrete transistors and a Zener diode in the avalanche breakdown region. Therefore, I have several questions relating to the use of the diode... How does ...
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8.6 ohm resistor is decreasing 3.97volts to 2.95 volts which is connected to zener diode i can't understand how it is happening

i'm trying to pass 3.3v to nodemcu from a 4v battery, For that I'm using a resistor of 8.6ohms and a zener diode of 3.6v. and the circuit diagram is as follows but when i simulate the circuit in ...
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539 views

Set a reference voltage: using a zener diode vs using a buffer

Given the following hysteresis comparator circuit: simulate this circuit – Schematic created using CircuitLab R1, R2 and OA1 are used to set a reference voltage for the comparator with ...
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457 views

Increase low-frequency gain of a cascode amplifier

I've been designing a noise generator (for fun) with the goal of getting a smooth frequency response between 10Hz and 10MHz. Since I don't have any "fancy" op-amps, I decided to go with a discrete ...
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240 views

Zener over voltage protection from DC hand crank generator

I have a board powered by a hand crank generator. Under normal conditions the voltage peaks at 18-20 volts. However spinning the handle violently will peak higher at 30+ volts. The generator runs ...
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209 views

Need help with boost converter for solenoid [closed]

I have a pull-solenoid with 32 ohms of resistance. I would like to supply 1 Amp to it with a 1 cell lipo battery: 3.7v nominal, 15 amp draw, 720mah. The power draw only needs to last for a fraction of ...
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148 views

How are voltage references established in low-power designs?

I've learned that most Zener diodes require something on the order to 20mA in reverse bias in order for Zener breakdown to take place. However, devices such as the LM431 "Adjustable Zener" can begin ...
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Zener Diode + fuse overvoltage protection for LEDs with constant current driver- fast or slow blow fuse?

I am working with a 6-axis robot (UR5) with a smart camera mounted on the end of arm, and I want to add a ring light to the camera lens which I will power using tool outputs from the robot interface. ...
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Zener diode characteristic graph

I'm having problem in understanding characteristic of zener diode. In the circuit zener voltage is 5.1V and source voltage is 10V. When i simulated in a circuit simulator i got the voltage vs time ...
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Why is 5.1V the standard Zener voltage and not 5V?

Looking on Digikey there are ~1300 results for 5.1V Zener diodes compared to 6 for 5V ones. Is there any physics-related reason for this or is it something else?
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How to use Zener Diode in Parallel RC circuit

What I'm trying to do is allowing the current to move through only one component. In the circuit shown, DC voltage is running two components (Z & C), also charging the capacitor When voltage cut, ...
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Calculating the voltage of zenerdiode

We got an example exercise in which we need to calculate the voltage and current in certain places of a circuit with a zener diode with different input voltages (ranging from -10v to 10v). Most of the ...
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How to mathematically simulate a zener diode

I would like to simulate a circuit with a resistor and zener diode for various voltages in an excel spread sheet and need a way to model it.
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Question concerning Zener diodes

This is a general, hypothetical question concerning power dissipation and zener diodes. It's hypothetical in the sense that I don't have the question in front of me and I don't have any further ...
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Is there such as thing as an ideal Zener diode?

I was trying to clamp voltage down across a 2.7 V supercapacitor and by measuring what is going on was reminded that Zener diodes have both a very soft "knee" region and a leakage current I can't ...
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219 views

Zener diode with high source impedance

I have designed a boost converter with a 400V output which uses a PFC IC For regulation, the IC measures the output via a potential divider which is fed into a pin on the IC The IC is looking for ...
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315 views

How do zener diodes, silicon diodes, and base-emitter junctions differ in reverse breakdown mode?

Here's datasheets for all of the above, and what reverse breakdown-related information I gather from them: Nexperia BZV55-B10 10V zener diode Breakdown may damage the device for powers above 400mW, ...
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395 views

What is a zener diode's I_z rating?

I know that IZT is the test current at which the zener's reverse voltage is established. But what is IZ? (So I can enter the characteristics of one in CircuitLab.
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Output voltage at load resistor given figure [closed]

i tried to solve question this way. that 35-20-10= 5 volt will appear at 900 resistor. but i am wrong.Correct answer is 9.47 V. can you correct me ??
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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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What is the role of zener diode in this clipper circuit?

i don't know exactly why we're adding the zener diode. My guess would be that it functions as a voltage regulator but that's as far as i can go.
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How to solve zener diode circuits [closed]

Determine the range of values of Vi that will maintain the Zener diode of Fig. 7 in the “ON” state my assumptions : if Vz=V breakdown = 20 V then Iz will start flowing downwards and by increasing V ...
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LEDs vs. Zeners: what is quiet?

LEDs can be, have been and are used as voltage references. Standard LEDs in various colors are cheap and hence sensible when wanting a low accuracy low voltage reference. Remember that low voltage ...
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198 views

Why does my HV monitor circuit (sometimes) fry components?

simulate this circuit – Schematic created using CircuitLab I have a high-voltage monitor circuit that illuminates an LED when HV is present, shown above. A couple of these boards have worked ...
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871 views

Dealing with voltage spikes in BLDC motor drive

I drive a BLDC motor with an ESC. When using power from a LiPo battery everything works as expected. When I use a power supply, on rapid stops or slowdowns motor generates voltage spikes, which send ...
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273 views

Do diodes care about current? or only voltage?

I have a diode, specifically a Zener diode and I connect it in the following configuration: simulate this circuit – Schematic created using CircuitLab So that it acts as a voltage clipper. My ...
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142 views

Capacitor voltage rating in a zener-only stabilized mains supply - 35 V rating OK for 24 V?

I have to replace a smoothing capacitor in the "power supply" of a mains operated device. The stabilization is done with two 12 V Zener diodes in series. The supply uses a capacitor and resistor to ...
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Using 3v3 zener, with actual max 3.5v, to protect Raspberry input?

I'm interested in making a serial connection between an Arduino and a Raspberry. I'm using a SN74HC14N inverted Schmitt trigger to provide 5V logic from the 3v3 signal. (3v3 TX -> 1A; 1Y->2A; 2Y-> 5V ...
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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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Current passing through zener diode at base of NPN

I want to find current through Zener diode. correct answer is 10.3 mA. I tried to solve it this way. i found Ib( base current) Ib = Vcc-Vbe-Vz/10 so 20-10-0.7/10 = 0.93 mA. My answer is wrong. Can ...
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270 views

Question about Non-isolated Buck Converter [closed]

I have a tutorial problem about buck converter with MOSFET, anyone can help? During the test of the non-isolated buck converter (see the circuit below), when we measure the gate signal, there is an ...
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Transistor(BJT) Zenner diode voltage regulator circuit

calculate the regulated output voltage of a series voltage regulator circuit as shown in figure Given \$ R_1 \$= 3.3 kOhm, \$ R_2 \$= 2.2 kOhm,\$ R_3 \$=5 kOhm,\$ R_4 \$=10 kOhm, \$ V_z\$=10 V. ...
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350 views

Zener diode behaviour at operating limit

I am looking to select an appropriate Zener diode from the ZMM range for MCU input pin protection. They are specified at a Zener current I_ZT = 5 mA having a maximum impedance of Z_ZT = 90 ohm. They ...
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How to calculate ripple voltage in this bridge-rectified zener-regulated circuit?

For one of my labs I need to design a power supply with the ripple less than 1% of the nominal 4.7 V value (since Vz = 4.7 V) and calculate its load regulation. I know that the ripple will most ...
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545 views

PNP with zener diodes circuit

simulate this circuit – Schematic created using CircuitLab I am really struggling to understand how this circuit works theoretically. What will be the currents through the resistors? My ...
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588 views

Zener diode regulator with transistor

Before I work on the simulations, I am struggling to understand the voltage regulated circuit theoretically. I try to vary the V1 DC supply, V2 provides a constant DC voltage of 12 V. The zener (D1) ...
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38 views

Complementary output flatlines with higher current

I have a rotary encoder whose output uses an NPN and a PNP transistor to switch between something slightly less than the high input voltage (~17V input) and ground. I need to trigger 5V TTL from this,...
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208 views

Zener diode behaviour

Take as an example this circuit: this question is in fact related to a previous one. When considering a variable, decreasing load \$ R_L \$, $$ R_L I_L = R_L (I_S - I_Z) = V_Z $$ can be constant ...
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471 views

Voltage protection of PNP Open-Collector Pull-Down Resistor Circuit

Circuit Consider the following U-Shaped Micro Photoelectric Sensor Panasonic PM-T54P with two PNP Open-Collector Transistor outputs: I chose the supply voltage to be 12V DC. In the place of the two ...
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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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593 views

Opamp Zener Regulator Configuration

[No TL;DR provided] I am an undergraduate electronics engineering student and I am working on designing a linear bench top power supply with foldback current limiting. Inspired by designs all over ...
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Voltage-boosted switching boost converter

I refer to my previous question which may be found here. With the LT1172 the highest output voltage of the booster is about 60 V, or slightly more. Now I need more, say 100 V. Linear technologies' ...
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Zener Diode vs Voltage Divider vs DCDC Converter vs Voltage regulator IC

As the title suggests I am looking for a way to drop 12V to 5V**. Which circuit should I use? And if I am going to use one, Why can't I use the others in the list ? I am looking for: 1. If the current ...
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Identify a surface mount zener diode with a four digits code?

I'm reverse engineering a circuit which provides a digital signal over a single pin. It is made up of only three components, all of them surface mount. One component I assume is a zener diode. (The ...
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How do TVS diodes work?

I'm aware of how Zener diodes can work as voltage clamps, but how do TVS diodes work in terms of physical construction? The Wikipedia article explains what they are used for, and a bit about their ...
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Charging a supercapacitor with a zener diode

I have a dc source which gives 5.5V and I want to know how to give only 2.7V to the supercapacitor for charging. I'm thinking about this circuit : What are the limitations of the circuit? ...
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Different Zener Diode Symbols

In the past I have seen two different symbols for a zener diode. One shows the complete "Z" shape on the cathode, and one shows more of an "L" shape on the cathode (see images below): What is the ...