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Questions tagged [diodes]

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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Sinotimer progamable timer relay

Unfortunately it burnt due to power short circuit or another reason. After open the circuit I have found two problems: The resistor acting as a fuse is burned which was wire wound fuse resistor. The ...
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1answer
68 views

Please help to identify SMD diode

The markings are: 1112 1Z The package is 2010 (5025 metric). Any clues will be much appreciated. Apparently it is located right at the 12V input. On DMM / ...
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1answer
10 views

Junction Potential parameter in Keysight Genesys

In the Nonlinear Diode model in Keysight Genesys there is no forward bias voltage parameter. There is a "junction potential" (Vj) parameter, however. I've never seen or heard anyone use the term ...
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4answers
303 views

How is dynamic resistance of a diode modeled for large voltage variations?

The resistance of a diode changes with the voltage across it which is called dynamic resistance. If the voltage across the diode is constant we can find the dynamic resistance from the slope of the I-...
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2answers
44 views

Puzzled with parallel forward biased diodes with common anode and different cathode voltages

If two identical diodes are in parallel and forward biased such that their anodes are at the same potential but their cathodes are at different potential how can we find the anode potential? As an ...
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51 views

How does a rectifier demodulate radio information and why does its capacitance matter?

I read in a forum “A point contact diode like OA79 should be used for the demodulation of AM. This diode is a signal diode and is having a low junction capacitance because of its special construction. ...
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21 views

What is the best way to isolate power hold-up circuit?

I an currently designing a hold up circuit for a computer and I need to keep this load isolated from other circuits that don't need to worry about a brief loss of power. The research I've done has ...
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1answer
84 views

Logic gate on negative signals

I need a logic gate to check if A or B or C is negative voltage (referenced to the ground). It does not matter if the output is positive or negative logic (as long as it is in positive voltages) Does ...
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1answer
38 views

Looking for Diode L V 108 datasheet [on hold]

What is this diode and what is it used for?
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3answers
135 views

Will this schematic work - basic LEDs + strips

This is my first LED project for my art bike and after a good chunk of reading, I wanted to know if the circuit would run properly. LED are green 5mm from AliExpress. Forward voltage 3V-3.2V, 20mA ...
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2answers
82 views

Diode rectification

Why don't I use this circuit for full wave rectifier instead of Bridge rectifiers or Center tapped transformer type rectifiers?
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2answers
106 views

What is the best method for reverse voltage protection of a microcontroller

When connecting a USB to TTL cable to flash a microcontroller (ESP32), I want to provide reverse voltage protection because connecting the pins in the wrong direction is easy to do and will destroy ...
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2answers
69 views

Forward diode characteristics not starting from zero Ampere

Why the current is not starting from zero, whats the diode characteristic when current is near zero? Reading the datasheet for N-channel 60V MOSFET, I encountered this source-drain characteristic of ...
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3answers
114 views

Why won't a diode allow current when there is a return path

I am watching this video. https://www.youtube.com/watch?v=vwJYIorz_Aw at 1:05 it shows a diode as "blocking" current, even though there seems to be a return path through the diode and back to the ...
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2answers
78 views

How do I know that this BJT is in the saturation zone without having to simulate it?

I have to find the working zone of this BJT, for different values of P, by using a simulation software like Simulink. But I would like to know how to do it manually. The way I learned is sort of ...
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1answer
72 views

Meaning of discontinuity in a diode circuit, analyzed using a simplified model for the diode

In our microelectronic circuits class we have been taught about the following simplified model for the diode, \$(v_D < V_k \implies i_D = 0) \land (v_D = V_k \implies i_D > 0)\$ where \$i_D\$ ...
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2answers
56 views

Powering 5 fans with a LTC 3780 : should I protect it against induction effect?

I want to power 5 fans in parallel (12V 0.80A, each) using a adjustable power supply (DIY, made with an LTC 3780 connected to a 24V 15A PSU and mini Voltmetre). I read that a fan could destroy the ...
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4answers
91 views

Supply white/blue led with 3V3 at constant current

I need to drive a white/blue led at low constant current (about 10mA.) To do that I usually use the schematic below, but in my case I can only supply the LED with 3V3. Since the typical forward ...
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1answer
48 views

BJT Cascade Difference Amplifier Exercise

I need help with the exercise. The questions: Add or Design Components to have a current source I=2 mA at the picture. Draw equivalent small signal,low frequency model. Find Ai, Zo, Zi. If ...
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29 views

Diodes used in MRI coils

I'm working on an old QHC EL Load ACS/NT head coil and found what I'm sure is a bad diode, but there are no markings or numbers on them, only two colors blue and red. Red being the anode side. As ...
6
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3answers
1k views

Can I use 1000v rectifier diodes instead of 600v rectifier diodes?

I plan on doing some wiring but the directions are asking for 1A 600v rectifier diodes. I could only get my hand on 1000v rectifier diodes and before I continue I want to make sure this is safe as if ...
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0answers
45 views

I have two inputs which are switching between 12V and a GND. I want to have a wire where I always have 12V and one with where I always have GND

As in the title. Assumptions : The inputs are switching at the same time. If one is 12V the other is GND and vice versa. I have tried coming with a solution on my own : using an OR port (diodes) to ...
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0answers
61 views

Dual diode connection for return path

I want to use the following dual diode for the return path with a fuse. The diode is dual with each diode rated 25A, the cathode is the same, which means I have to connect it like in the figure? Do I ...
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40 views

Depletion region in metals

Can we create a depletion region (just like in diodes) between two dissimilar metals?What would be the use of that?
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1answer
36 views

How to connect a fast recovery diode with 3 pins?

I have a fast recovery diode, part number D30FD60K, I would like to know how I have to connect it. The diode will be used as the return path in parallel with a fuse. Like shown in the diagram. Pin 3 ...
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3answers
60 views

Controlling 1 fan with 2 different computer power supplies

Ok here is my scenario: Because our 2 gaming computers are pretty noisy, we moved them to another room in a closet. There are vent holes to the outside of the building, and now that the summer comes ...
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1answer
58 views

Diode circuit analysis solution

I am not familiar with circuit analysis, although I can manage to solve basic circuit. However, I am currently stuck with a problem and I am not sure about the solutions. If anyone could have a look ...
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1answer
89 views

Can a stepper motor flyback diode discharge a coil when connected in serial to the coil and opposite to the current?

On a circuit taken from this page http://www.opend.co.za/tutorials/steptut1.htm The last circuit shows two diodes positioned in reverse polarity to the current. It is supposed to protect against the ...
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3answers
67 views

Replace some LEDs with diodes in relay circuit

I need to know if I can replace the input LEDs (IN1, IN2, IN3, IN4) by a diode or resistor and if this can help me to reduce the voltage consumption generated by these LEDs. The circuit is a 4 relay ...
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2answers
98 views

What kind of magic is energizing the coils in this simple stepper motor driver?

Looking at this web page, i found a simple stepper motor driver circuit https://www.electronicshub.org/stepper-motor-driver-circuit/ The problem is, i just can't understand how it can work when the ...
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0answers
26 views

Finding the current in a circuit containing diodes

I am working through a problem where I am determining the state of a diode, as shown in the picture below. I have first assumed that both diodes are conducting, and to check this, I am checking to see ...
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2answers
70 views

Diodes - minimum forward conduction current

I've been working on a GPS tracker which is intended to run/idle on a battery for an extended length of time (2+ years). The tracker uses an accelerometer (LIS3DH) and remains in a sleep state until ...
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1answer
41 views

Determine polarity of IrED with multimeter

I have an infrared LED as part of an IR transceiver, and I want to determine its polarity. As the device is unmarked, finding its datasheet is out of the question. And, as it is infrared, seeing it ...
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1answer
37 views

Can I take the voltage across diode to be same as the input voltage in a limiting circuit?

My doubt is a trivial one, can I take VD1 and VD2 to be V1? If so doing that doesn't make sense to me 'cause when the current flows VD1 is certainly not equal to V1. This isn't a Homework question, ...
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1answer
66 views

What's the conduction angle for a full wave rectifier with filter capacitor?

Shouldn't the conduction angle for a full wave rectifier with filter capacitor be twice that of a half wave rectifier with filter capacitor? The conduction angle for a half wave rectifier with filter ...
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4answers
90 views

Voltage error when connecting a zener diode

I am working on a project where i need to measure the battery voltage and send the measurement to a uC, which is powered by 3.3V. The voltage divider is projected as shown before: As input we have ...
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0answers
32 views

In a forward bias diode, why do electrons continue into neighboring holes?

When an electron from the n-type side fills a hole on the p-type side, it fills the valence shell. For reference, consider this video: https://youtu.be/7ukDKVHnac4?t=230. I learned in chemistry that ...
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2answers
3k views

What is the role of the transistor and diode in a soft start circuit?

Please can someone explain the purpose of both the transistor and diode in this soft start circuit
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2answers
104 views

Disadvantage of using a Schottky diode across the LDO input/output for reverse voltage protection

I'm studying a linear power supply circuit design for my future project and I started off disassemblying a good(expensive) LPS out in the market. While I was studying it, there was a part that I wasn'...
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0answers
47 views

Overvoltage protection circuit - Serial zener diodes and op-amp

I need to prevent people from plugging in batteries with incorrect voltage. The 2 cell LiPo with voltage range from 6.4 to 9.8 V is alright, EN=1. But 3 cell LiPo is too much and I need the below ...
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2answers
1k views

Can a zener diode with a higher power dissipation be used in place of the original one in an audio amplifier?

Following my Marantz PM-68 repair question, I would like to change a faulty zener diode used in the amplification stage. I don't really understand the purpose of this diode but I guess it's used for ...
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2answers
64 views

Op amp diode clipping

I am creating the following diode clipping circuit: The input signal, Vin, offset is removed and the signal is amplified using an op-amp. Then there are two diodes designed to clip the signal to +/- ...
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3answers
394 views

In microwave frequencies, do you use a circulator when you need a (near) perfect diode?

I am confused with the "diode concept" in microwave frequencies. As far as I could read, I found that even small signal Schottky diodes have a non negligible capacitance, that may perturb the signal ...
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2answers
53 views

Relay Driver with 24VDC Relay… Zener diode?

I am part of a physics project group, and we are trying to design a relay driver. Our Relay is rated at 24VDC (it is a Tyco Electronics 1432826-1). What zener diode (or regular diode if that would ...
0
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1answer
59 views

Bulk current injection - Resonant frequency of ESD protection diode CAN bus

Link to the application note that I'm referring to below. I was going through an application note by On Semi, System Level Surge Suppression Solutions for the CAN Bus -AND8253/D, where it says that ...
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1answer
50 views

Push-pull output stage and driving circuit function

simulate this circuit – Schematic created using CircuitLab Hello, what is the exact purpose of the C3 and C4 capacitors, two diodes and R3 and R4 resistors in this circuit used to drive the ...
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27 views

Finding output voltage of a circuit containing diodes

I am given a circuit below and I was hoping to clear up some misunderstanding I may have about conducting and non-conducting diodes. I am not sure which part of my knowledge is wrong, although I know ...
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3answers
75 views

Finding current through a diode

I am asked to find the current through the second diode, as shown in the image below. I have gone through my procedure to find this current, and can not figure out why my answer is wrong. What I did ...
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1answer
53 views

Should I replace this Schottky Diode?

electronics noob here. Just looking for some advice on replacing a part for a ebike motor controller. I think I may have shorted one of the schottky diodes (part) by running current through the ...
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2answers
36 views

Magnitude of \$I_{CBO}\$ in a typical transistor

I read in a book that \$I_{CBO}\$ doubles for every 10 degree rise in temperature and hence contributes to thermal runaway. However I am confused since essentially it is the reverse saturation current ...