Questions tagged [reverse-breakdown]

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Ideas for protecting the input of an opto against high reverse voltage

I've been given a circuit to test and pointed out that the potential reverse voltage across the led in the opto will exceed the spec. The cct is a dual input with an opto on each channel, which feed ...
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2 votes
2 answers
239 views

BJT Base-Emitter Reverse Breakdown

In the following (partial) circuit, the transistor is usually in its regular forward active mode. However, when the supplies collapse abrubtly - e.g. during power-down - the base-emitter junction can ...
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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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TVS diode specs - clamping voltage lower than breakdown voltage?

Having read this app note (and a few others) and quite a number of TVS datasheets, I came across one that is bugging me a bit. All of the TVS datasheets that I have read so far describe the the ...
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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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Base-emitter reverse breakdown and current

I have a circuit as follows, simulate this circuit – Schematic created using CircuitLab which provides a control current to an OTA as \$i_\mathrm{abc} = (3.27\mathrm{V} - V_\mathrm{in})/R1\$. ...
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Why does the Zener diode's simulation model differ so much from datasheet specifications?

I was trying to design a circuit with a Zener diode by using its datasheet specifications and noticed there was a very big difference between the design and the simulated circuit. After inspecting the ...
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2 answers
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Interpreting the differential resistance of a Zener diode

I have this Zener diode - 12V rated C part. I just want to understand how to read the differential resistance column on table 8 for Zener current of 1mA and 5mA. Suppose I give an input voltage of 16V ...
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Zener Diode Reverse Current

I have this - Zener Diode - 12V Reverse Voltage On the table 8, I can see the ranges for the 12V reverse voltage is between 11.4V and 12.7V for the "C" selection part. But this value if for ...
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1 vote
1 answer
139 views

Potentially unusual LED failure

One of the LEDs in a plug equipped with over-voltage protection does not light up when the device is plugged into the 230 V mains. It has worked well for a while since the product was purchased. An ...
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reverse bias of the gate of an N-channel enhancement mosfet

So how negative can I drive the Vgs of an N-channel Mosfet before damage occurs? Datasheets specify BVDSS and BVGSS but these are "forward" breakdown voltages -- ie the absolute maximum Vds before ...
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Can reverse breakdown voltage be used to simulate lifetime aging of phototransistors?

As phototransistors age, their responsivity to light decreases (a fixed amount of light generate less photocurrent). To simulate long-term aging of phototransistors in a short period of time, one can ...
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2 votes
2 answers
685 views

Any importance to TVS 'parallel' vs 'series' Topology?

I am working with an existing schematic which has bidirectional TVS surge protection, laid out like this: simulate this circuit – Schematic created using CircuitLab The TVS diodes are ...
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Why do diodes adjust to reverse breakdown voltage when we apply a voltage more than the breakdown voltage?

When a voltage(neglecting sign as I am considering reverse bias region) more than the reverse breakdown is applied then why diodes adjust themselves to reverse breakdown voltage? Please provide an ...
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2 votes
1 answer
237 views

HFA3096 transistor array breakdown voltage

In the book Learning the Art of Electronics, one of the labs is to build a differential amplifier with a CA3096 transistor array. The author admits that the chip may be difficult to find and gives the ...
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what limits the maximum voltage of this optocoupler (6N137)?

In the datasheet it is stated that the maximum VCC voltage is +5.5V.(https://www.vishay.com/docs/84732/6n137.pdf) Because ive been told to question everything (and i have enought of them to kill one ...
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How to find the resistance of a diode operating in reverse breakdown region?

I am tasked to find the small signal resistance of a diode operating in reverse breakdown region (not forward bias). Method 1: Is using the small signal resistance formula correct even in the ...
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2 votes
2 answers
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Find cause of diode destruction from destroyed diode itself

Is it possible to find the cause of power diode destruction, ie. if it was destroyed through: reverse overvoltage spike (reverse breakdown and subsequent thermal destruction due to reverse ...
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Led blinking with one NPN transistor [duplicate]

I am using scheme as shown below to blink an LED. But I'm using 9V battery source instead of 12V. I tried to use capacitors in range 100uF - 500uF to increase delay between blinks. Questions: ...
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2 answers
2k views

How to solve a a full wave rectifier with two diodes and a ground in the middle?

This is the problem I am trying to follow along with the solution but I don't understand what is happening, how do I handle the random ground in the middle?? is the node between d1 and d2 40Vpeek and ...
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2 votes
2 answers
376 views

Can a reverse biased diode be driven past its voltage rating but with current limited to few uA

If, for example, a Silicon diode rated at 100V is reverse biased at 200V (long term, not just very briefly) but in series with a few MegaOhm resistor such that the reverse current is limited to one ...
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323 views

Huge reverse current leakage in fast recovery diode for boost converter

I have a boost converter circuit that will boost 12 V to around 180 V, the circuit is works pretty good but there is huge reverse current in fast recovery diode right before the load. Here is my ...
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55 votes
5 answers
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Are LEDs better than we think?

Conventional wisdom about LEDs says their maximum reverse voltage \$V_{R(max)}\$ is quite limited, usually in the 5V-8V range. So, for experimentation purposes, I wanted to bring an LED into ...
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4 answers
1k views

diode selection for large current reverse bias, small current forward bias

I'm designing a circuit where I want to pass a small test current from one leg, but block a large "firing" current (rocketry) coming from another leg in reverse bias. I have a 5vdc indicator line (...
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2 votes
1 answer
419 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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2 answers
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PC817 input features

I'm designing a new circuit and I need to know if PC817 allows AC voltage input around 230V. I've tried with DC Voltage but never AC Voltage. Does anyone know if it operates with AC input?
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10 votes
1 answer
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Are reverse biased transistors stable?

The usual circuit (found widely across the internet) for a true random number generator's (TRNG) entropy source is a reverse biased transistor like so: Q1 is typically a 2N3904 as it has been found ...
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4 votes
6 answers
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maximum reverse voltage applied to a resistor-LED configuration

Consider the simple circuit below: simulate this circuit – Schematic created using CircuitLab LED datasheet: link Does the applying of a reversed 36 volts to this circuit damage the LED? ...
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2 votes
0 answers
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Diode emission coefficient and saturation current

I have created a Zener diode model in LTSpice, and now I am trying to simulate it with different values of the saturation current (IS), emission coefficient (N) and breakdown voltage (BV) using Spice. ...
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2 votes
1 answer
510 views

Protect phototransistor from emitter-collector breakdown

I'm using the ADC on the reset pin on an ATTiny85 to detect an IR level. The reset pin is disabled in the fuses but I would like the ability to "recover" the fuses and reprogram the device. The ...
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10 votes
1 answer
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How protective diode protects transistor from breakdown?

Please, explain the process of breakdown; how exactly this protective diode protects the transistor? In a Horowitz & Hill book, "The Art of Electronics", 2nd edition, in "Chapter 2 - Transistors" ...
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