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Questions tagged [diodes]

Diodes are semiconductor components made from a P-type (or metal in Schottky diodes) and N-type material (usually silicon, but germanium, selenium, and gallium arsenide can also be used), that allow current to flow in one direction only.

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Diagnosis and Replacement of 2N1101 transistor

I have a circuit board with 3 transistors on it, all of them are 2N1101. I'm trying to diagnose the problem with the board with the diode tester on my multimeter. I found 2 of the transistors have a ...
ch_7scal's user avatar
0 votes
1 answer
30 views

Part number of this IC marking "R2. 8"

Can anyone please help me define the part number of this part marking "R2. 8" in the picture below?
Bang Duong's user avatar
3 votes
2 answers
95 views

Trying to identify a vintage (1992) diode

I'd like to identify the vintage diode at position D15: This diode is found on a PCB from a 1992 Mercedes 300D (W124) Convenience Control Unit (it controls the windows, sunroof, etc.). I don't think ...
Hal Purdy's user avatar
0 votes
2 answers
79 views

How to know what size diode to use for inductive spiking?

I am making a simple Zener flyback circuit for an inductor. What current rating should the diodes be sized for? Could I use a 1 watt Zener diode because the voltage spike only lasts a few microseconds,...
Justin Osgood's user avatar
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0 answers
48 views
+50

The role of Q33 and the connection of pre-discharge circuit in the BMS circuit

I'm trying to understand the following circuit which is taken from the TI's TIDA-010216: I don't understand the role of Q19, D29, D30 and Q33 in the circuit. According to this post, it seems that Q19,...
S.H.W's user avatar
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1 answer
55 views

Usage of two PSU in parallel for WiFi router using Schottky diodes

I have Wi-Fi router which is powered by AC adapter with nominal output 9 V, 0.6 A. Due to power outages I have bought USB DC-DC adapter 5 V ⇾ 9 V and power it from power bank/power station. Router ...
1n5817's user avatar
  • 13
0 votes
1 answer
52 views

Part Identification and Circuit clarification

i am trying to repair a laser driver circuit. Apparently, it was connected to a lab power supply (the driver is rated 4-5,5V, 8A) and someone turned the knob, so it got way higher voltage. I ...
Boldar's user avatar
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0 answers
44 views

Discrepancy in Diode Simulation Results between LTspice and Standard Test Conditions [closed]

I'm currently working on simulating diodes in LTspice and have noticed a discrepancy between the simulation results and standard test conditions (1000 W/m2, 25 degrees Celsius. The results have been ...
Mohamed Haj hamido's user avatar
3 votes
2 answers
616 views

Flyback Diode Forward Voltage

Using this link as reference. Question 1: From my understanding, if the applied forward voltage across a diode is much greater than its rated forward voltage the diode will potentially fail. Based on ...
brye's user avatar
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4 votes
1 answer
615 views

What is this symbol on the manual for a Yaskawa servo drive?

I'm attempting to wire a Yaskawa Sigma-V Series AC servo drive to a Rosetta CNC, and I came across this symbol, a triangle that has one line in, one line out, and what seems to be a return line ...
AGreatUsernameChoice's user avatar
2 votes
1 answer
139 views

Chip Identification - TVS diodes

Can someone please confirm that these are bidirectional TVS diodes, I cannot find the datasheets for these anywhere, but they look to be them.
Cillantro's user avatar
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1 answer
74 views

Please help me identify this IC - top marking "CEK"?

Please help me identify this IC - top marking "CEK" such as picture below:
HNLinh's user avatar
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1 answer
70 views

Can anone identify this IC marked `55JT`?

Please help me identify the IC pictured below:
HNLinh's user avatar
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0 votes
1 answer
47 views

Identify IC marking LCSZ

Can everybody help me IC LCSZ such as picture below
HNLinh's user avatar
  • 173
5 votes
1 answer
119 views

About diode question solution

While solving the diode question, a point like this stuck in my head, I did the solution in this way, but I ask you to help the community For X value; (I thought it should be found with a voltage ...
smartony152's user avatar
3 votes
2 answers
781 views

a question about silicon diode

Which of the options is correct for a Si diode? a) It conducts if the voltage applied to its anode is greater than that applied to its cathode b) If the voltage applied to the cathode is greater than ...
manrupe's user avatar
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1 answer
47 views

Identify Zener Diode with label of SF on an Antminer S21 hashboard

I have the following Zener Diode I need to replace, but I'm not sure how to identify it as there are 100s of diodes out there. The only marking I see is SF. How does one go about identifying this ...
Patoshi パトシ's user avatar
0 votes
1 answer
74 views

How to Properly Select Resistors and Capacitors for a Voltage Reference Circuit with BJTs

I am working on a reference voltage circuit and I am having trouble when selecting the appropriate resistor and capacitor values. The circuit involves OP07 operational amplifiers and transistors (...
Cheche Romo's user avatar
2 votes
3 answers
508 views

Ideal diode in parallel with resistor and voltage source

Sorry if this appears to be a silly question, but it is a concept I am having trouble with. I don't quite get how to arrive at this plot. The current from V1 as a function of V1. If V1 > 0 then I ...
Nero's user avatar
  • 189
1 vote
1 answer
49 views

Changing the Limits of the Graph When Trying to Model the Shockley Equation in MatLab Shifts the Position of the Curve [closed]

I have been trying to create a piecewise linear model of a diode through curve fitting. While trying to implement the code below, I ran into a strange bug that is causing my output curve to shift to ...
Parker's user avatar
  • 27
0 votes
1 answer
37 views

DC-DC convertor-SEPIC architecture

I'm working on a SEPIC DC-DC convertor, in the reference design from Texas instrument there is MOSFECT which is derived by DR pin of the main controller (LM3488) as follows: There is an diode (D4), ...
Andromeda's user avatar
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1 vote
1 answer
64 views

Help me to identify SMD diodes marked '1DN'

Help me to identify SMD diodes marked 1DN.
Ksm's user avatar
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2 votes
2 answers
199 views

Powering on a laser diode that exceeds PSU max current

I have a laser diode that I want to test (just seeing if it turns on). However, the threshold current is past the 10A that my bench power supply can supply, hence I can't generate any light. How can I ...
AnttiP's user avatar
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0 votes
1 answer
65 views

What is the purpose of the diode in this complementary class B amplifier?

For this circuit, why did we use a diode between the bases of the two transistors?
FISqrt's user avatar
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0 votes
2 answers
104 views

How can I choose the resistance value in a limiter circuit?

Problem: A signal must be limited at +/- 100 mV. Assume constant-voltage model for the diodes where V_D,on = 800 mV. Design the required limiting circuit. Attempt: I set V_D,on + V2 (but was flipped ...
Nero's user avatar
  • 189
0 votes
1 answer
50 views

Type of diodes for 9V [closed]

I am looking to protect a 9v battery against a 12v battery. I know the question has been asked already and someone did put a circuit up as well but I don’t know what type or what model number I need ...
Sajhid Buckreedun's user avatar
4 votes
7 answers
1k views

Freewheeling diode in a capacitor

I hope this is not too trivial a question. I know that a freewheeling diode is connected across an inductor to eliminate the sudden voltage spike that occurs across an inductive load due to ...
KaleM's user avatar
  • 473
1 vote
1 answer
75 views

One thing I don't understand about the diode graph [closed]

I have such a circuit. I need to determine the output when such an input is given. But the only thing I understand is the way I have drawn it below. The current enters from the negative direction. ...
manrupe's user avatar
  • 73
1 vote
1 answer
55 views

Understanding the components of backlight circuit of digital watch [closed]

I am not a hardware engineer. I studied basic electronics 15 years back in school days, so you can consider me a noob. I have a digital watch in which all the features (time, alarm, chime, etc) work ...
Naveen's user avatar
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0 votes
2 answers
149 views

What is the purpose of this circuit inside a solar lamp?

I'm trying to get started with electronics, just as a side quest. I found this little circuit inside a solar lamp I had. I'm trying to understand what its purpose is and why it uses its components, ...
Jeremy D'Souza's user avatar
1 vote
1 answer
46 views

Can I control Neopixel LEDs with this circuit? Is this a viable level shifter?

I recently purchased a microcontroller board (Pimoroni's Automation 2040 W) and I would like to control Neopixel-like LED strips (WS2815) which work with 12V. Since I am using a 3.3V microcontroller (...
ElectroEnthusiast's user avatar
0 votes
2 answers
61 views

Heatsink can cause a shortcircuit what kind of problem occurs?

I'm not sure what will happen in this kind of scenario I'll share the photo of two diodes and basic connections below. These two diodes tab points are actually connecting same node because of tab is ...
MSB's user avatar
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1 vote
1 answer
55 views

Ideal 3 Phase Rectifier [closed]

I am working on a 3 phase PFC and implementing third harmonic injection. In order to do so, I use the min-max method. This would be trivial in an MCU, but everything is being done in analog. I have ...
Stiddily's user avatar
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1 vote
3 answers
59 views

Diode Circuit Input-Output Plot Question

My attempt: When V_in is very positive, the diode is off, and V_out = R1/(R1+R2) * V_in When V_in is very negative, the diode is on and so: V_in + V_D,ON {constant voltage model} = V_out But I am ...
Nero's user avatar
  • 189
1 vote
1 answer
175 views

How to identify this IC FG97

I'm trying to identify an IC labeled FG97 1847 17145. It is a 16-pin SMD.
HNLinh's user avatar
  • 173
0 votes
1 answer
75 views

Two formulas for defining RMS and average of a waveform through a diode [duplicate]

A textbook problem where we have this given current waveform through a diode. We are required to determine the maximum and RMS values of it [ Irms and Ip ] giving the average current= something ...
Spencer's user avatar
  • 39
1 vote
2 answers
84 views

Temperature dependent characteristics of a diode

I understand why the forward voltage decreases in the diode due to the increase in temperature (since the intrinsic carrier increases and that decreases the voltage since intrinsic carrier and the ...
Fredrick's user avatar
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0 votes
0 answers
27 views

Verify whether the Motor Driver has PWM Support

I was looking for a single channel motor driver with a supply voltage range of 6V - 12V and a continuous current range of 2A. I came across a motor driver IC called SS6285L. This motor satisfies the ...
Kailash Kumaravel's user avatar
2 votes
2 answers
479 views

How does this over-voltage protection diode work?

I saw this schematic for the RPi power supply with USB-C. I do not understand how the D1 diode acts as over-voltage protection. Can someone explain? The image is from the RPi documentation.
void_brain's user avatar
1 vote
1 answer
64 views

Identifying SMD diode - markings ST e3 G (next line) DUK (next line) G3 635 (or b35)

I am trying to identify the following diode. I can see it says DUK G3 but am unsure on the last part, if it’s meant to be 63S or b35 or something like that. I’ve tried multiple Google searches and can’...
user1148760's user avatar
0 votes
1 answer
108 views

Why do diodes have different models?

When soldering some stuff, I accidentally reversed the direction of the diode, and now I can't get it out. I was thinking of cutting its leads, but the leads would be too short to solder back on. So, ...
Andy K's user avatar
  • 369
0 votes
2 answers
92 views

Powering LED's From Two Different Relays? (Complete Novice)

I am attempting to install auxiliary reverse lights in my vehicle and have come to the end of my useful knowledge. I am confident I could simply install new LED's splicing a relay into the existing ...
Wire_licker's user avatar
2 votes
1 answer
236 views

Help me SMD diode identifying

I need to identify a diode. Can you please help me? Package : 1,60x1,30x0,80 (probably SOD-323). I'ts a diode (TVS).
Maxime BOISDRON's user avatar
0 votes
2 answers
91 views

Cant figure this out [closed]

Below circuit pulled from homemade-circuit.com, Practical Voltage Regulator Project with Feedback for Enhancing Output Accuracy, https://www.homemade-circuits.com/simple-voltage-regulator-circuits-...
hhsting's user avatar
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1 vote
2 answers
62 views

Can you explain why change in cathode voltage appears on anode pin?

I simulated a circuit using LTspice, as shown in the image I attached. I applied a variable signal to the cathode terminal of a Schottky diode. I observed the same signal (with a Vf difference) at the ...
MCav's user avatar
  • 31
0 votes
4 answers
158 views

Should a diode be placed between the output of voltage regulator and the battery?

When applying constant voltage to a 8-volt lead acid battery using a 7809 voltage regulator, should a diode be placed after the output pin and before the battery, anode to the output pin and cathode ...
SA A's user avatar
  • 11
6 votes
2 answers
297 views

Analyzing Diode Quartet Switch

I am trying to understand how this diode quartet switch works. I am having trouble dealing with the two current sources. I can think about what happens to the voltages in the circuit, but how do I ...
Axodarap's user avatar
  • 157
0 votes
1 answer
26 views

Does the unidirection TVS diode like SMAJ15A be used on DC lines to protect the IC or Converters from negative Peak, clamp down to -0.6V?

Most of the DC- DC converters have absolute maximum down to -0.6. If bidirectional TVS diode is used then negative peak cannot be clamped near to -0.6v, in this is the case can we use the ...
Raviteja Cherukuri's user avatar
1 vote
1 answer
52 views

While Identifying Transistor terminals with Multimeter diode mode, why does B-E junction yields a slightly higher forward voltage then B-C junction?

I've learned that multimeter produces a small current in the diode mode and then measures the voltage drop across the diode. So a high resistance should produce a high voltage difference. Since ...
Osama's user avatar
  • 13
1 vote
0 answers
52 views

How fast and far do electrons move in a diode during reverse bias?

When I have looked at videos on how diodes work, they make it seem like the electrons move extraordinarily quickly during reverse bias and quite a bit to expand the depletion regions. However, I would ...
John's user avatar
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