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. ...

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70 views

What type of zener diode is this?

What type of zener diode is this? The thin band is blue.
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2answers
53 views

Transistor not supply enough current

I am trying to run a 100W 32V Led with a DC-DC boost converter from a 6 volt battery, and I want to make it so it will shut off when the battery voltage gets low. So I am using a TIP122 transistor ...
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2answers
143 views

SMD vs THR Transistor for Relay

Designing a Relay control from a MCU's GPIO, there are some requirements to take into account. Coil Voltage: 3V Coil Resistance: [36-45]Ohm Relay Voltage: 250Vac // 30Vcc GPIO Voltage: 3V3 Max GPIO ...
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1answer
33 views

MOSFET gate protection zener diode math .please help

My circuit's voltage input can range from 6V to 12.6V. I want to use a p-ch mosfet for reverse bias protection. However, the FET I want to use has a maximum VGS of +/- 8V, so I have to protect it in ...
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1answer
341 views

What is the purpose of transistor in this circuit?

"A zener diode voltage regulator is inefficient when the supply is used with equipment that draws high current. When a supply must deliver a lot of current, a power transistor is used along with the ...
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1answer
50 views

Explaination of high current zener transistor regulator circuit

This is a high current zener TRANSISTOR regulator circuit. I want to know What does "high current" mean here? How is this circuit working as a zener regulator? What is the purpose of transistor ...
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6answers
123 views

3V6 Zener Diodes With Very Poor Accuracy

I have a question about the regulation accuracy (or lack of) of a 3V6 Zener diode. I wanted to confirm that I wasn't doing anything stupid. I set up the standard test circuit shown below. No ...
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2answers
96 views

Can this circuit be called a 12v,5A zener regulator?

If this circuit can be called a 12v,5A zener regulator, then I know that 12v here is the varying input voltage. What is the 5A current here,I mean where can it be represented in the picture?
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0answers
53 views

How can I add redundancy to the flyback diode protection across an inductive load?

Dear StackExchange users, I want to add redundancy to a flyback diode system that is protecting an N channel MOSFET from flyback of an inductive load but I don't know how to accomplish this! I am ...
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1answer
54 views

How different is the performance of TVS vs Zener diode in flyback protection

So far I know that it is possible to protect a Switch, MOSFET, Relay from flyback with different kind of diodes: One diode: It is simple but it affects the speed of valve One diode + a resistor: ...
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1answer
31 views

Zener voltage resolution at fixed current and load?

Under a fixed optimum current and negligible load (ie being used as a reference into an opamp) how steady is the voltage of a smoothed zener? The scenario is a zener carrying a current of 5mA in its ...
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1answer
47 views

Cant figure out a solution for 27V, 3A supply

I have a pretty weird situation I need to produce 27V, 3A from a supply of 27.5V, at first I thought of using a zener as the voltage regulator but I could not find a zener of over 81mW, with zener as ...
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2answers
79 views

I require a more comprehensive explanation of the function of zener diodes

I would first like to establish that I am simply the most basic of beginners in the realm of electrical engineering, and that complex terminology will only cause me to ask more questions. A circuit ...
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1answer
117 views

How does flyback diode decrease the response time of a solenoid valve

Dear all StackExchange users, I want to make a circuit consisting of 8 valves. Each valve has 55mH and 33 ohm. I want to control them with an Arduino board and a proper MOSFET. Valves reaction time ...
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4answers
222 views

Zener diode voltage too low

I'm trying to regulate 12V to 4.7V with a zener diode. (I'm doing this to protect an AVR's gpio pin, so the current is very low.) I tried the simplest circuit with the zener, but it does not work as ...
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2answers
74 views

Zener Diode not working as expected

Maybe I don't quite understand how zener diodes work but, I thought that they would block a reverse voltage until it reached a certain threshold (the zener voltage) and above that, they would allow ...
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3answers
46 views

Question about Z-Diode circuit and measurement

I am currently diving in in embedded development using ATMega Microprocessesors. I have now a question regarding Z-Diodes. My circuit is powered by a 9V battery that gets through an IC7805, thus ...
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3answers
470 views

Can a Zener diode that protects a switch against inductance when the switch opens, affect turn on speed of the valve while you close it again?

As you probably know, in the applications that the turn off speed of the solenoid valves are crucial, the simple flyback diode is not effective. Some people put a resistor in series with the flyback ...
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1answer
50 views

Zener diode minimum and maximum current

Why is the Iz max given before Iz min in this zener diode catalog? If you look at the list of diodes at the bottom, you can see that the maximum test current is given first. Is there something ...
2
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1answer
169 views

Using NPN BJT with a P Channel MOSFET to switch 3.3V to 24V

simulate this circuit – Schematic created using CircuitLab I have some 3.3V I/O on a PC Board. When an output is switched on, I need to switch the 3.3V output voltage with a +24VDC and ...
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1answer
98 views

What is the purpose of the zener diode in this circuit?

Related: What is the purpose of the resistor on this MOSFET's drain? This is a circuit taken from a TI reference design (http://www.ti.com/lit/df/tidr687/tidr687.pdf) to drive an LED matrix - ...
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1answer
79 views

Where do you put the gate-protection zener diode in an NMOS H-Bridge?

Do you even include it for an NMOS H-bridge? Because typically I've only ever seen them in NMOS/PMOS bridges, not full NMOS bridges. (Inductive load) The protection zeners would go here right?
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3answers
135 views

3v3 Microcontroller controlling a MOSFET that needs 5V

I'm designing a heater controller that has a primary input voltage between 12 and 24V. Everything except the heater runs on 3V3, including microcontroller, LED's, potentiometers and the MOSFET. The ...
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2answers
89 views

Please explain the circuit (current regulator test circuit with Zener diode)

my mind needs refreshing so could someone please help explaining analysis of this circuit. It is used for testing a current regulator (LED driver circuit) ('I' in the image). The regulator current is ...
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3answers
149 views

Fast 220v AC power failure detection

I'm building an AC-Detection circuit. I want to detect when the AC power has failed ASAP so that I can react very quickly. (like 1-3ms should be enough time) This was my first idea. It works in ...
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1answer
94 views

Are Germanium Zener diodes still obtainable?

I need a Germanium Zener diode for a shot noise generator circuit. If I am correct, Silicon replaced Germanium for use in diodes and other semiconductors because of the fact that Germanium diodes have ...
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1answer
29 views

Question about the operation of a zener for a rapid relay release

This is a follow up question to Zener voltage selection for relay?. The following image was taken from the previous question I'm trying to grasp exactly what is happening in this circuit. My ...
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1answer
42 views

Zener voltage selection for relay?

This question is similar to Zener Diode Selection for Relay but the focus is in how to select the voltage for optimum or near optimum release time. With the circuit below, how does one select the ...
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1answer
52 views

Waveform Clipper

I need help solving this circuit. It's supposed to be a waveform clipper and I already simulated it, however I want to know how the circuit works and so far I haven't been able to analyze it properly: ...
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2answers
122 views

Passive voltage drop from 6V DC to 5V DC for 3W circuit

I plan to put an Arduino onboard of my hub-generator powered bicycle circuitry. Currently, I have a circuit consisting of: 6V/3W AC hub generator (variable frequency and power); Rectifier bridge; ...
0
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1answer
56 views

What would cause a zener shunt regulator to have Vout < Vz?

I'm restoring a old motorcycle and the headlight is very dim. Upon inspection, there appears to be a shunt regulator. I infer that the part they call the 'regulator' in the diagrams is just a zener ...
0
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1answer
51 views

Zener diode in stepper motor driver with TPL7407L

In TPL7407L's datasheet, there is a stepper motor driver schematic as below There is a zener diode denoted as "optional". However the 'COM' pin is connected to 'VSUP' directly. The 'optional' means ...
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1answer
60 views

Single input terminal for multiple voltage inputs

I am designing a board for which I want to have single input terminal for voltage. Board is microcontroller based(Atmega328) so the voltage coming to uC(Vcc on picture) should not exceed 5V. How I ...
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1answer
33 views

BZY97C47 zener diode datasheet questions

The BZY97C47 data sheet (I found no direct PDF link) confuses me on several points. I fail to find straight forward information about the maximum allowed forward current from the data sheet. Also, ...
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2answers
80 views

Are my zener concepts wrong?

If a battery of 60v with internal resistnace 4kohm (in series) is connected to a zener diode of v_z=10v in parallel and a load resistance of 2kohm in parallel too, what will be the currents in ...
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1answer
45 views

Passive ringing on PCB causing noise

I have a PCB that is exposed to a sharp inductive-voltage collapse, around 100V/100nsec. The voltage collapse happens when the current through a transorb reaches zero. When this happens, the board and ...
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votes
3answers
182 views

Virtual GND resistor dividor vs zener diode

I was having a discussion with someone about using a virtual gnd for an opamp circuit. One way to provide the VCC/2 voltage is with a voltage divider made of two precision resistors (and a capacitor ...
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1answer
160 views

AVR USB to Serial Converter; Quick Question

I have a TI86 calculator that I've had for over 7 years now. Well I'm letting a lady friend on mine borrow it, and I was going to load it up with some apps for her. And the tradeoff is happening this ...
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1answer
123 views

Reduce power supply voltage

I'm trying to build the power supply described here. R1: 1K8 1/4W Resistor C1,C2: 4700µF 25V Electrolytic Capacitors D1: Diode bridge 100 to 400V, 1.5 to 4A D2: LED Any type ...
2
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3answers
354 views

Lower Voltage With A Zener Diode

I am trying to lower the voltage from a 9V battery to 5V for use on an Arduino pin. I bought a 5.1V zener diode from RadioShack. Will this do what I want? Do I have to lower the amps as well? It looks ...
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3answers
358 views

Please explain this circuit (CNY70, Zener diode) [closed]

I am trying to build a new (Arduino based) controller for a machine that contains a circuit that uses a CNY70 to detect RPMs in a motor. The circuit takes a 5V input and I accidentally gave it 24 ...
2
votes
2answers
72 views

What are the electronics components that have characteristics like Neon Lamp?

Neon lamps have higher breakdown voltage than its operating voltage. When brokendown, it acts like a zener at its operating voltage.
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2answers
91 views

Alternative to V divider for high currents

I am looking for suggestions as to how to supply power to a gate drive optocoupler i am using. The supply being used is a 25V (rms) ac supply and intend to supply 10V DC at around 500mA+ from my ...
0
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1answer
53 views

Voltage regulation vs relative voltage tresholds?

There is a part of my circuit that uses resistance to output a voltage, in which is compared to a voltage threshold to output a digital signal. However +Vcc can vary and any voltages too far from 5V ...
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votes
2answers
281 views

Zener Diode Selection for Relay

I am using a Zener diode along with a flyback diode with a relay in order to speed it up a bit. This works very well but I am currently using a rather over-sized zener from the inventory. For ...
0
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1answer
136 views

Why use two power sources when designing a voltage regulator using a zener diode

I am currently designing a voltage regulator using a 5V zener diode. I am wondering why some people choose to use two power sources instead of one, what would be the benefits of this ? the circuit ...
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1answer
263 views

What are the correct zener diode and PTC fuse size?

Noob here. I need to add overvoltage protection to a small, portable solar power system I'm putting together. The solar PV array has a loaded voltage in the 23-26v range and an open circuit voltage ...
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3answers
275 views

How a zener and a schottky diodes protect laser diode?

I purchased a strain relief wire SR9C which has a small protection circuit for a laser diode. It says to contain a zener and a schottky diodes which protect the laser diode from ESD. By looking at the ...
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4answers
127 views

Running 3,6V MCU on full 4,25V Li-ion battery

How can I run 3,6V MCU on a fully loaded 4,25V Li-ion battery? Normally the battery would be 3,6V, but on fully charged it is 4,2V, it would kill the microcontroller. Load is 10mA, minimum voltage is ...
5
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1answer
441 views

LED as Zener: is this a good way to lower the BOM cost?

I had an old AM radio board designed to operate with a 3V CR2032 coin cell. I want to revitalize this old junk with as few parts as possible and convert it into a USB-powered AM radio with a built-in ...