Diodes are semiconductor components made from a P-type and N-type silicon material, that allows current to only flow in one direction.

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ATtiny85 absolute ratings for outputs?

The ATtiny85 datasheet specifies an absolute maximum negative voltage for any pin of -0.5 volts relative to ground. Consider this partial schematic: MOSI and MISO are the respective ATtiny85 pins ...
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4answers
94 views

Cool White LED bulbs: Are they “full-spectrum”?

I don't have much knowledge on LED lights and find the technology quite fascinating (yes, I know, it is not that knew!) I have read that in order to create "white" light, LEDs actually need to emit ...
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45 views

Why can current flow through the reverse biased base-collector junction (N-P junction) in a BJT with a forward biased base-emitter junction?

If the base-emitter junction of a BJT is forward biased, then current can flow through the reverse biased base-collector junction (N-P junction). This disagrees with my understanding of the PN ...
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2answers
62 views

How do you choose a diode for a 5v to 3.3v clamping circuit

I have a logic input that is 3.3v and I want to be able to allow it to interface with either 3.3v or 5v input signals w/o worrying about it being damaged. I would like to use a resistor with a ...
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1answer
59 views

voltage regulators destroyed — protection diode needed?

I have the following basic circuit: As I was flipping the button to turn the relay on and off, I noticed sparking from the voltage meter, and it eventually caught fire, releasing the magic smoke ...
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1answer
37 views

SMD diodes identification

I'm trying to identify the SMD components on a contactor control circuit. They are from General Semiconductors and have the labels: YR103, WX104, and RZ102. I think they are diodes, but I'm not sure ...
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49 views

How ICBO gets amplified to ICEO in BJT when base is open

I have been doing some reading about ICEO and ICBO, but couldn't really understand how ICBO is getting amplified (1+ beta) times to reach ICEO, in the open base condition. This is my understanding ...
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42 views

ICEO, ICBO physical interpretation in BJT

I am stuck with the equation: ICEO = (1+β) ICBO My questions are: What is the physical interpretation of this equation? Will both the currents exist simultaneously? Are any of the reverse currents ...
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2answers
265 views

Why is there so much overshoot in my LED circuit and how do I prevent it?

I'm trying to PWM a 5 meter RGB LED strip with a microcontroller. With this setup: simulate this circuit – Schematic created using CircuitLab I have built it on a breadboard and probed ...
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1answer
100 views

How much power/intensity IR Diode should have to be seen from 30-50 meters

How much power/intensity IR Diode should have to be seen from 30-50 meters by camera with IR pass filter? Must be a good point in a photo. Should be seen in a day light. Preferably with wide angle. ...
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51 views

Single Phase Diode Bridge Rectifier - Inductive Smoothing Question

So I don't understand how the answer is 2.124 volt-seconds when if you put the equation through a calculator it comes out as -0.174. Is there an additional mathematical step to do on the cosines in ...
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84 views

A small circuit with two diodes

We have circuit like this: There's no internal resisters in batteries. Is \$\frac{I}{J}\$ equal to zero? If it is nonzero what is the voltage between the ends of the lamp (assuming the lamp has ...
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71 views

Diodes and CMOS 4060 (14-stage counter)

Take a look at this popular circuit for a fridge alarm based around the 4060 binary counter (http://free-electroniccircuit.blogspot.co.uk/2012/02/refrigerator-alarm-schematic.html): One thing I ...
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2answers
114 views

How does a Schottky diode work?

There are no spare positive/negative charge carriers on the metal side of the diode, so the spare positive/negative charge carriers on the semiconductor side can not diffuse into the metal and ...
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2k views

Why do some diodes have a glass package?

Put simply, why do some diodes such as most Zeners and Schottky diodes have a glass package as opposed to the more traditional plastic package? Is it ease of manufacturing, thermal properties, or ...
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141 views

Make a zener diode out of a MOSFET

Does anyone know if its possible to wire up a MOSFET transistor as a zener diode? I have been happily making normal diodes from my MOSFETs by shorting the gate and the source simulate this ...
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34 views

E51A818 = 1N5818?

I have a DeWalt DW9116 charger with a fried diode. This was caused by reverse polarity connection to a battery. It has numbers E51A818 printed on it. The only diodes I can find with 818 in their ...
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90 views

Diode rectification on a device

I have a Peltier (TEC) module, with diodes in series with each lead. (see image below) I'm not quite sure what the specs are for the diode, but it says 130 on one line and SB560 on another, so I ...
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62 views

Laser diode M140 current driver

I am trying to build a driver for my M140 laser diode. I made a circuit following a guide. Then I made a test load. When I change the pot value to the minimum I get a maximum current of <100mA on ...
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Can an operational amplifier circuit be made entirely out of diode Nand and Nor gates?

I'm not sure whether this question has been asked before, but in researching my question, I came across this user's post (at If-else decision structure using op amps or any other non-programmable ...
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1answer
59 views

Modeling diode connected transistor in differential amplifier

I have question about the analysis of common-mode gain of BTJ differential amplifier with active load on the Sedra Smith book. In this book, the differential-mode gain \$Ad\$ is derived based on the ...
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4answers
121 views

Is it reasonable to use a current limiting diode in place of a fuse?

I'm trying to source some fast-blow 5mA or 10mA fuses but Littelfuse has discontinued the only reasonably affordable ones I have found. My circuit when operating properly will not output more than ...
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3answers
78 views

Diode in parallel with two DC sources

Please help me to find the answer for the following question from Flyod 9th Ed. Determine the voltage across the diode in the following figure, using the complete diode model with r'd = 10 Ohms and ...
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2answers
86 views

Center-tapped Full Wave Bridge Rectifier

I'm designing a high-voltage power supply for a plasma experiment. I have a center-tapped ignition transformer (50:1) that I'm using to step up the voltage from 120VAC to 6kVAC and then using a full ...
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2answers
78 views

Difference in real diode characteristics vs shockley equation

I was wondering about the voltage drop in real diodes (0.7 V in Si diodes, 0.3 in Ge diodes etc.). According to my experience this drop is linked to the used material, but the shockley equation which ...
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1answer
69 views

Using to diodes for OR'ing in OVP comparator

We have the following scenario: over-voltage protection IC (MAX18590/86) is placed in front of a buck regulator in order to protect (obviously) against excess-voltage at the input. Normally the ...
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1answer
149 views

Circuit diagram for uninterrupted usage of a 12V 1A device using 12V 7Ah battery with auto charging and full charge cut off

I have a modem which runs at 12V 1A, also I have an UPS battery of 12V 7Ah. I need to design a circuit so that during power outages my modem works from the battery. Also, a circuit to charge the ...
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93 views

Choosing the right diode?

What are the general steps and things to know to choose the right diode for the right project?
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0answers
34 views

Diode bridge working only as half recitifier [duplicate]

I am trying to simulate diode bridge using 12. In the image below you can see the circuit and the simulation of the circuit. So my question is, why does this circuit does not behave as full-wave ...
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1answer
60 views

Catch diodes in switch mode power

I am wondering about catch diodes in the context of switching power supplies. I have read all the books that are the norm in designing a SMPS, but all of them don't or barely touch the subject. My ...
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1answer
40 views

Semiconductor diode barrier potential

I have little confusion regarding barrier potential (or built-in voltage) and cut-in voltage of diode. Are these are same or what is the difference between built-in voltage and cut-in voltage in ...
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1answer
52 views

Battery supplying different voltage

I 'm trying to build a portable device running on battery. It needs power at 2 different voltage: 3v and 4.5v Is doing something like this a good idea ? if so, what type of diode should be used ...
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4answers
104 views

Will voltage or current determine a diode drop for this battery charging circuit?

I am using a li-ion battery charger IC that regulates an output to 4.2V. I have a schottky diode in series with the output that then connects to the battery. How do I determine the voltage drop? If ...
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107 views

Low profile capacitor

I am trying to make a 24VAC to 5VDC converter. My constraint is to keep the height of the entire power module to as small as possible (ideally < 5mm) I have the buck converter design with the ...
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1answer
33 views

Reverse biased breakdown

Is the reverse biased breakdown of a rectifier diode a reversible process? (that is if the voltage is reverted to a value within the specification range will the diode behave as expected of an ...
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1answer
120 views

LM7805 and Zener Diodes

I'm boosting an LM7805 to 16V using Zener diodes in series at the GND pin (pin 2) of the 7805. The Zener Diodes I'm using are 1 of each of the following: 3.3V, 3.0V, and a 4.7V. Now theoretically I ...
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53 views

Why are resistors used in a Zener clamp circuit?

A data acquisition channel is fed by a signal which first passes through a clamping circuit as I draw below. Here in the figure Output goes into the data acquisition board after a 8V clamp circuit: ...
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2answers
75 views

Can I make pulsing light using AC as source, a diode and a LED?

I'm new to this branch of physics hence my stupid question. I know that diodes are used to make current flow in only one way. If I connected an AC source to a diode and the diode to a small light ...
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2answers
75 views

How to protect bistable latching 2 coil relay with diodes?

I know that a revers diode is required to protect a DC coil relay. But to protect this relay RT314F05? It has 2 coils, are 2 diodes enough?
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145 views

What can this component be?

I have this anemometer (wind speed meter). They provide some specs. But not the circuitry. It basically outputs pulses via a reed switch. So I opened this instrument to see its circuitry. Here is ...
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minority carrier life time? Why is it important for devices' switching speed. Why not majority carriers?

I am trying to get my head around why would and silicon engineer care about the minority life time carrier and how does the minority carrier affect the switching speed of PN junction. Why is it so ...
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3answers
146 views

Best way to drop 12V fan to 7-9V? [closed]

So my Xbox one PSU died and microsoft doesn't sell official ones yet, so I bought a third party one and the fan that is in it is a 12V blower fan with 2 wires running right to the board (it says 12V ...
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2answers
64 views

Diode identification

I'm trying to develop a replacement for a BLDC motor driver board and since my first attempt resulted in a few burned components now I'm trying to use the same components they used on the original ...
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1answer
82 views

Ideal diodes and applications

simulate this circuit – Schematic created using CircuitLab Question: The input signal V(s) is a square wave of \$\pm\$20V (peak) at 1Hz. Sketch the output waveform V(o). Clearly mark the ...
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154 views

Solving Clipper Circuit containing battery and resistance in series

I have learned to solve clipper circuit with and with out battery in parallel to the output node. But have no idea what to do if a resistance also connected with it in series. There is nothing said ...
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3answers
131 views

Understanding the PN-Junction Built in Voltage

I don't like asking duplicate questions but I couldn't find one that was quite the same. I apologize if it is similar to another. TL;DR: How can a charge neutral substance have a potential? Why ...
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1answer
145 views

Zener diodes Eagle library

I need to make a PCB, and the only software I have is Eagle. All the other parts are listed in my libraries, but where can I find a library that has DIODES INC. - MMSZ5226BS (Zener diode)?
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What is the diode for in this 555 circuit?

Here is a schematic of a 555 setup to create a single shot voltage sawtooth pulse across the capacitor C2. It also outputs a square wave pulse on pin 3. A (reversed biased) Zener diode is used ...
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2answers
283 views

Considerations for solar powered thermoelectric cooler with fan

I am building a food cooler for camping this summer. My plan is to build a thermoelectric cooler that is solar powered. My cooler is looking much like this: including a CPU fan on the hot side ...
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2answers
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Car Gear Indicator [closed]

I'm new in here and I'm very new to electronics and have a very little knowledge about it. I'm trying to do a project in where I have a car with manual gears 1,2,3 & 4. Each will be represented by ...