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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47 views

Lowest breakdown voltage diode, [on hold]

I'm looking for a diode which has the lowest breakdown voltage, about 1 mV or lower. I wanted to limit the signal amplitude to 1mV. I would be very grateful for specific examples.
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92 views

The name of the design I came with using diodes [on hold]

Have designed those diodes to make 12volts cause I was having only 7volts, I came with it to boost up the bolts but I forgot of the term to describe my design.
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1answer
80 views

Diode and op amp exercise

\$ R_1=1.2 k\Omega\$, \$R_2=2k\Omega\$, \$R_3=8.2k\Omega\$, \$V_R=15V\$ Exercise: For which value of \$V_i\$ the diode is conducting? Find \$V_o\$ as a function of \$V_i\$. Attempt solution: ...
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27 views

Controlling motor card with NI 9472 DO module

simulate this circuit – Schematic created using CircuitLab My goal is to simply turn on/off a 24VAC Motor. It is being driven by a card that I was originally just supplying 24VDC with from an ...
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1answer
33 views

Electronic Circuit with Opamp and Transistor to pull down a reference voltage via a diode. (Voltage Limiting)

I have a circuit which I have designed to pull down a voltage via sinking current into the opamp output. When the source signal is of higher output impedance this works fine, but when the source ...
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62 views

About over heating of my diodes driving my popcorn machine motor [on hold]

I have designed a popcorn machine but the motor needs 12volts DC system of which I put a transformer of 1.4A, Surprisingly it got blown.today I went with a transformer of 4A its bringing the same AC ...
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54 views

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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3answers
108 views

Circuit to detect if a battery is charging

I'm trying to detect if the battery in this circuit is charging or not by comparing the voltages across the diode. The battery is not charging if it's at a voltage higher than the charging input. For ...
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5answers
1k views

Am I testing diodes properly?

I decided to test some diodes that I have, using a multimeter to measure their forward bias voltage. I set my multimeter to voltage test and connected the diode across: I tested a bunch of different ...
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1answer
60 views

Diode operation mode between 0 and 0.7V

For a silicon diode that starts conducting for 0.7 volts, we say that it is directly polarized when its voltage is 0.7 or greater and we can represent it with a voltage generator (of 0.7V) in series ...
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45 views

5V vs. 3V diode protection circuit

I'm using USB cables in an very unconventional way (don't ask, we had a barrel full of USB cables left over from something else) to connect between boards with 3v battery power and also not following ...
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3answers
61 views

Arduino nano resetting after solenoid valve fires

I'm trying to control small, plastic 12V solenoid valves with an Arduino nano. I have an Arduino nano hooked up to a Sainsmart 4-Channel 5V Relay Module, and finally connected to the solenoid valves, ...
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41 views

Diode sine wave shaper - location of break points

I'm attempting to generate a sine wave from a triangular wave using the diode breakpoint method where the sine wave is approximated by multiple straight-line segments. Where should the breakpoints be ...
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1answer
117 views

What is the purpose of these diodes?

What is the purpose of these didoes? I couldn't find it because I don't know it's name. Thank you. simulate this circuit – Schematic created using CircuitLab
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3answers
89 views

Heatsinking considerations for Common Cathode Rectifying Diode

I am using this as rectifying diode in full bridge configuration in one of my power supply designs. My questions are regarding heatsinking of the diodes. They are as follows: Do I need to use ...
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66 views

Can I replace the transistor in this circuit (Esaki oscillator) with a Zener diode?

Can I replace the transistor in this circuit (Esaki oscillator) with a Zener diode?
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1answer
45 views

Finding the output of a node with two diodes (kind of full-wave rectifier)

Maybe this question sound stupid, but I really suck at electronics. I have this circuit here: simulate this circuit – Schematic created using CircuitLab and i want to find the values of ...
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3answers
45 views

Switching between battery and external power sources with reverse polarity protection

In my design, I will use AA batteries to power the electronics board. As a requirement, also it should accept the power from external power supply (12V) - The board should automatically switch from ...
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2answers
76 views

What is this type diode & transistor?

im new in electronic. i don't know 2 this component: maybe this is Diode Marking ST S56 Z424 i can't found reference this part. can anyone give me a link reference or similar part? Transistor, ...
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42 views

safe negative voltage divider to GPIO pins

this question comes from this other, trying to implement the folloging circuit to measure a -3V battery pack (2xAA) (I've to measure in that way, cannot swap or move GND): Digital PIN 6 will be set ...
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1answer
49 views

Sending flyback current to another inductor using crossed diodes

So, here is the context. We have two electromagnets (modeled as R1 and L1, and R2 and L2), their state is dictated by a microcontroller which sends PWM to Q1 and Q2. The signal sent to Q1 and Q2 is a ...
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1answer
74 views

Schottky Diodes as Full Bride Rectifier

I need to make a 75-100vdc high current power supply. I do not have any high current diodes or bridge rectifier ic’s but I do have a load of scrap switching power supplies. Could I take 4 of the(lack ...
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1answer
46 views

Connecting two power supplies and preventing reverse feeding either [duplicate]

Is there any way to prevent current from passing through a certain wire without actually cutting off the power from that line. To be clear, I'm using 2 power source and because of "even with 0.0001v ...
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65 views

Combining 2 power supplies [closed]

I know this isn't a good idea or a possible idea. Can I use 5 mbr20100ct in parallel to add reverse current protection to my 2 power sources? One is running at 5v at 50A and the other is running at ...
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2answers
57 views

Find instant in which diode starts conducting in transformer full wave rectifier

We have the following circuit V2 = Vs/a; a = 10; Vs = 100sin(wt); w = 200 rad/s; Each of the diodes is modeled by a fixed 0.8 V drop when conducting, and by an open circuit when OFF. Find the ...
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45 views

Stable current source with discrete components

The purpose of this is to compare and learn different circuit topologies, not use of the shelf solutions which obviously provide cheaper, simpler and better results. Considering this requirement (no ...
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3answers
75 views

Performing small signal ac analysis with non-linear components

I have written a circuit simulator that uses Kirchoff's voltage and current laws to solve linear circuits containing capacitors, resistors, inductors and op-amps (where the op-amps are assumed to be ...
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31 views

Reverse polarity diode, which diode is better: SB140 or 1N5819

I want to add reverse voltage polarity protection into my circuit to protect the components in my Arduino robot. But i want to know which diode has the edge on the other: SB140 or 1N5819? Or is there ...
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1answer
40 views

Finding the sinusoidal input voltage of an amplifier

An amplifier has a linear transfer characteristic passing through the origin (0, 0) and with output voltage saturation at L+ = 10 V and L– = –8 V. The amplifier gain is 100 V/V. What is the ...
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1answer
67 views

How to find the current and voltage of this circuit?

I have this circuit with a Z-Diode in reverse. Find U2 and I2? I solved the fist circuit. U1 = 0.7V, I1 = (15V-0.7V)/1kΩ)= 14.3mA The results for are U2-8.2V I2=6.8mA but I just can't figure out ...
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1answer
99 views

What's the purpose of a diode across capacitor after voltage regulator?

I'm learning about power supplies at university and I have created 2 or 3 PCBs of this stuff, but recently I saw this schematic: I have no idea of what exactly these diodes do in this circuit. Can ...
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2answers
68 views

What's the voltage transfer characteristic of this power driver circuit?

[Exam problem for an instrumentation course] Can anyone help me understand how this circuit works? I'm not too familiar with power circuits... This somewhat reminds of a BJT class B amplifier (but ...
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1answer
63 views

Diode questions

I need to replace a diode on my GCM harness and have a few questions. Does a diodes reverse conductivity depend only on the voltage applied to the diode or is current a factor as well? I know ...
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2answers
58 views

5v relay module not working with dc adapter [closed]

I have a setup with a relay that disconnects mains voltage for a project.the problem i have is that the relay works fine when i connect it to the arduino and power it from a laptop but i changed the ...
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1answer
74 views

How do I show that this is an OR gate?

I need to go through the 4 cases where v1 and v2 are either 0V or 5V, and then use that to show the voltage value of the output, Vo is either low or high. However, I think I'm hitting a contradiction ...
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1answer
64 views

What is (was) this component at ZD102 (top left, next to powered serial connector)

Part at ZD102 is overloaded with too much current and blown. It's three legged, with two legs on the south side and 1 on the top. The left side (white in the picture) is blown and has since ...
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1answer
78 views

Build a circuit so that you can determine the I-V curve of a diode

The question I have is: how can I design a circuit so that I can determine the I-V curve of a diode. I've found this one: But is that a smart circuit or can I find a better one? Thanks for any ...
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2answers
61 views

Electrodes and number of pins in vacuum tubes

I am confused regarding the terminology 'diodes', 'triodes' etc and the number of pins in these elements. If a diode has a cathode, an anode, and a supplementary anode (the control grid or plate) and ...
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3answers
84 views

Zener diode purpose

Can someone explain what the purpose of D3 & D4 are in this circuit?
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1answer
58 views

How can I identify an SMD diode marked SX DG?

My question is based on the attached picture of a diode which says SX DG but I can not find this diode. The diode is taken from PoE 63v part of IP camera attached with MB6s ke47 SXDG SX DG
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1answer
70 views

Using an IR diode as an emitter and receiver?

At the recent Maker Faire Berlin, I was told that LEDs can be repurposed as photo diodes. I assume the same is true in the infrared range. This sounds like a nice solution for building a transmitter. ...
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1answer
68 views

how to lower a power bank USB 5.1v /2.1amps output to 4.5v to power a 150 lumens LED flashlight [closed]

I would like to use a power bank to power a 150 lumens flashlight 3 AAA batteries operated ( https://www.harborfreight.com/ultra-bright-led-portable-worklightflashlight-64005.html ). I already ...
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2answers
36 views

Increasing diode clipping influence

I'm working on a guitar pedal distortion circuit and I've been experimenting with introducing diode clipping into the signal. My question is, how can I increase the influence this diode clipping has ...
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1answer
48 views

diode identification help A7

I'm trying to figure out what this diode is. The marking indicates "A7" and also has "t36" stamped on it suggesting maybe a 1N4007 rectifier diode. However, when I test it with my multimeter I get a ...
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0answers
58 views

Simple parts to stop “phantom power” from entering circuit

I have a circuit here which can sometimes program a microcontroller. I think a big problem here is that "phantom power" is introduced in the circuit because when I'm ready to program it, I plug the ...
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1answer
35 views

Diode direction for Door Pin Trigger

Which direction should the diode, cathode or anode, be facing for a car security alarm wire? Below is a diagram. When the doors are closed, the wires are testing at 10.1 Volts, settings on the ...
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1answer
72 views

AC Diode Question

I am a noob in electrical circuit boards. I need to build a basic circuit board that allows me to open 2 valves at a time but the current should not flow to open an other valve down the circuit if ...
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2answers
52 views

Use LED as a latching diode

I am working with 74HC08 (AND gate chip). I have to assemble my circuit according to following image: Everything works fine, but I have suddenly a fancy idea to replace 1N4148 diodes with low-power ...
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2answers
67 views

Purpose for Shunt Resistor on Opto Isolator Input?

I was looking at a BeagleBone Black Cape and became curious on an input circuit to the BeagleBone GPIO (used for a NPN proximity sensor). Upon further reverse designing, I notice a // 220Ω shunt ...
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2answers
59 views

Back powering a switching regulator

It is pretty standard practice to clamp a signal to Vcc by using a diode and resistor. However, when this happens, some small amount if current (maybe ~50mA) is flowing back into the Vcc line. When ...