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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Why Diode resist the flow of current in reverse direction? [on hold]

In a reverse bias (when the diode is pointed against the current flow) it acts as a strong resistor.Why?
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50 views

Body Diode of a MOSFET

So for some MOSFETs, specially with Power MOSFETs, the body diode is a flyback diode that (as far as aI can tell) can be conveniently added to the MOSFET's bulk as there already PN junctions (correct ...
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16 views

Laser diode driver at high currents

I have a fiber array package laser diode which draws 30A at 2.8V. I would like to use it in a laser cutter project, but I don't know how to go about designing a power supply for it. I came up with ...
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49 views

Diode to control the direction of current or as a switch

I am not an engineer or have knowledge of circuits etc. I do not know how to do a schematics. I have a crude diagram of the circuit but I do not see an option to attach it here. If there is a way to ...
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1answer
40 views

How can I build a 2 input AND gate 24VDC PNP inputs and 24VDC output?

I'm trying to build an AND gate that takes two inputs from standard 3 wire 24VDC PNP sensors and provides a 24VDC output. I was thinking using some sort of diode resistor logic (link to circuit: ...
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1answer
22 views

Is it a good choice to use mbrb1545ct schottky for the 5 MHz signal clipper?

For my application, I need to clip 5 MHz(max) signal to stay within ±0.5 V. I selected two of mbrb1545ct Schottky to clip my signal. I selected Schottky because I think they are faster to turn on and ...
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1answer
70 views

What type of zener diode is this?

What type of zener diode is this? The thin band is blue.
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2answers
62 views

Unusual Component Inside Photo Multiplier Tube Base

I am attempting to diagnose problems with a PMT (Photo Multiplier Tube) in our lab. I have taken apart the base, and begun drawing the underlying circuitry. I have come across a circuit component that ...
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2answers
416 views

How does this button work without any circuit closing device?

This may be a stupid question, but I have searched online for a little bit and can't seem to find my answer. I am working on a circuit board that uses buttons that i've never seen before. These ...
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57 views

circuit help voltage multiplier

Hello I am using a breadboard and I created the circuit below. I am using Two buttons to gain and fade a voltage output. I am using a voltage multiplier because my source is only 5 volts and I want ...
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3answers
69 views

can dropped voltage be greater than forward voltage?

What I know is: forward voltage, Vf = The minimum voltage that is required to start current flow across the LED/Diode dropped voltage, Vd = The voltage that is used/lost across the LED/Diode. My ...
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1answer
117 views

LED indicator for DC voltage

I am planning to using a buck / boost converter to run a DSLR camera from my USB powerbank AND other power sources. For that module I want to build with the buck / boost converter, I need a simple LED ...
2
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2answers
196 views

Thermal power dissipation for a diode with heatsink

I have a circuit that has a diode that needs to support 3A through it. The supply is at 7.2V and is therefore ~22W. I have currently selected a schottky diode show here. Key specs are it can ...
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30 views

How do I design my protection circuit?

I am making a rectifier to input 80V AC at 10Hz To eliminate the ripples, I'm using a capacitor whose value is 5mF. It supplies a load of 10mW (Resistive). What are the protective circuits to be ...
2
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2answers
67 views

please help choose mosfet, npn, pnp, diode for my circuit

I developed a circuit which uses charge pump to supply a current mirror. Simulation works, I was able to get 40V and constant 10 mA at load < 4k. I breadboarded each charge pump and current ...
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1answer
20 views

Reverse breakdown voltage setting for the diodes in a solar cell model in SPICE

I want to simulate the reverse breakdown behavior of a two diode model solar cell in SPICE. The diodes configurations without considering the breakdown voltage are as below: ...
2
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1answer
47 views

Can I use a NPN Transistor as a Varactor Diode?

I am currently building a crystal controlled AM transmitter. The circuit that I'm using call for a NTE – 613 varactor diode (which will come in a few days). I was wondering if there was an alternative ...
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3answers
68 views

Digital Input Clamp Circuit Protection

To be able to connect some peripheral to digital input, I'm designing the circuit protection to avoid any possible failure due to over/under-voltage issue. So, I will add a clamp protection circuit. ...
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2answers
62 views

single phase rectifier

hello can someone pleas help me to solve this problem this is the scheme I cant recognize where the voltage can turn because all the diodes are blocked
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3answers
236 views

Determine adequate speed of flyback diode for a relay

I have already looked at this question which looked like it would provide the answer: How to choose a flyback diode for a relay? But it didn't, so I also checked out these: ...
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1answer
36 views

Will this temperature compensation work?

I have a circuit and as a part of it I need to measure the battery voltage under a load. Naturally I would need this load to be constant each time I measured it to accurately know the battery levels ...
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1answer
16 views

Avalanche diode circuit analysis of the current load

I have no idea how to work out this past exam question. I'm kinda sure is that the diode is an Avalanche diode, but I'm not even sure how Zener diodes or this work. All I think I know is that with a ...
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2answers
161 views

Diodes in Tachometer Circuit

How are the diodes helping in the attached ckt :-
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2answers
81 views

Is a flyback diode necessary when no sensitive chips are used?

I have had a look through all the information available about flyback or snubber diodes in a relay system and was hoping to confirm if one is necessary in my circuit or not. All the info about why a ...
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82 views

Diode and Op Amp

Can you help me finding the expression of Vo(Vi) and graphing Vo(t)? I have simulated it in multisim but i can not understand when the diode passes current or not.
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122 views

Relay Spike at Vdd

I have a problem with voltage suppression at the time of relay switching. I use a transformerless ac to 12v dc conversion circuit similar to (I use 12V zener and 470uf capacitor) : ![enter image ...
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1answer
51 views

Rechargeable Gameboy Color modification

I've been doing a little research online on how to make my Gameboy Color rechargeable, and I came across an instructable this guy made on how to make your GBC rechargeable using standard rechargeable ...
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1answer
69 views

Which diode is conducting and what are the operation points of the conducting diode?

In the following circuit assuming that diode's cutoff voltage is \$0.7 V \$ , I want to find operating points (voltage, current) of diodes \$D_1,D_2\$. simulate this circuit – Schematic ...
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27 views

Voltgage over time - 3-input or logic gate using diodes

I have the following circuit. The voltages u1 , u2 , u3 have the following voltages over time. I want to plot the voltage of Vo over time?? What steps can I follow?? Is this the graph I am ...
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69 views

Does a diode conducts with negative voltages applies?

If I have a diode(ideal one) and I apply -5 V in the anode and -4 V at the cathode then the diode conducts?? I have the diode characteristic in mind but the graphs refers to v. Is this v equal to ...
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1answer
75 views

Reversed biased diode polarity in circuit

I have to find the operating interval of the diode in the following circuit.. NOTE: The DC source has its positive pole grounded. My work so far is this.. \$V_i>-1.5 V\$: the diode does not ...
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3answers
105 views

Can you use diodes instead of OR gate?

I am building a computer and thought if I could simply use diodes instead of OR gates. Will this work with logic ICs such as the 74LS, 74HC and 75HCT series? Sorry if this is a stupid question, I am ...
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2answers
100 views

smd resistor and regular through hole resistor

My question is fairly simple. I am building an SMD LED board and i am limited in space. So originally i was planning on going with through hole resistors, but have it being i'm very limited on space ...
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4answers
222 views

Zener diode voltage too low

I'm trying to regulate 12V to 4.7V with a zener diode. (I'm doing this to protect an AVR's gpio pin, so the current is very low.) I tried the simplest circuit with the zener, but it does not work as ...
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27 views

Discrete IC Printed label

How can I identify a transistor PMOS, when I only know the printed label/legend in it "T9F"? and the same to identify a zener or diode, when I only know the printed label/legend in it "2U90"?
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26 views

Does zxms6004ff come with flyback diode internally?

As question above, does anyone know better about product from DIODES? I am using zxms6004ff, but not sure about if it comes with flyback diode internally? I read over their datasheet. It only says it ...
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1answer
65 views

When current flows why diode not makes any shortage in it

I konw that a diode works like the explained here. How does a diode work? but I have different question as I am not expert in Electronics, well i am showing you a very simple circuit which is below. ...
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2answers
108 views

Choosing Diodes for 3-Phase Rectifier

I'm building a rectifier to rectify a 3-phase signal for part of a school project, so I'm not working at these power levels without help and supervision. This seems to be an appropriate circuit as ...
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3answers
46 views

Question about Z-Diode circuit and measurement

I am currently diving in in embedded development using ATMega Microprocessesors. I have now a question regarding Z-Diodes. My circuit is powered by a 9V battery that gets through an IC7805, thus ...
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1answer
46 views

If you put a MOSFET in backwards does the impedance change?

if I stick a MOSFET that should be going (S-D) to positive in backwards, and make it (D-S) to positive, all the current drops across the diode instead. This diode then approaches an impedance of 0. ...
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1answer
64 views

Will a diode conduct if one side is floating and one side has voltage applied to it?

I have a circuit that has a battery output voltage of about 7V and can also have a charger input that when plugged in will output around 9V. The battery/charger power a microcontroller (regulated ...
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3answers
55 views

best way to rectify 30kv flyback output?

i have made a flyback transformer for some HV experiments and am hoping to get around 35kv from it, which i want to use to charge a capacitor, so i will need to rectify the output... i think perhaps ...
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1answer
50 views

Zener diode minimum and maximum current

Why is the Iz max given before Iz min in this zener diode catalog? If you look at the list of diodes at the bottom, you can see that the maximum test current is given first. Is there something ...
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1answer
77 views

Diode in parallel with resistor

SE, I've used the SE:EE forum search and several search engines internet and haven't found a single question similar to mine. But I don't think that it's that complicated, I'm just having a hard time ...
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71 views

Current sensing in H bridge for Stall detection-Purpose of Diode

I have a circuit, which is powered from two 1.5 V AA battery. It has a MCU and PNP - NPN Hbridge for driving motor. The motor (RF-300CA-11400) datasheet is here in this Link. The Motor will be turned ...
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1answer
33 views

AC alternative for DC diode short-circuit protection

I have two sensors (represented in the schematic below by a switch) connected to a light. If one of the sensors trips, I would like the light to switch on. The sensors and light are directly on AC, ...
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1answer
75 views

Can I replace a 1N4148 diode with a 1N4007?

My PC game controller broke and since I have some old PS1 controllers I was thinking about converting one to PC. After some googling I found all I need is a parallel port plug and some 1N4148 diodes. ...
0
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3answers
95 views

What's the purpose of the diode in this selectable supply voltage circuit part

I'm looking at the power supply part of the schematic of SparkFun's Pro Micro Arduino board, which has a jumper to enable or disable a voltage regulator to select between running the board at 3.3V or ...
0
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1answer
68 views

1N4148 Diode for 3V-5V PWM

I have 2 PWM ports, one generates 5V PWM and another at 3V. But only 1 will be generating at a time. However, their output is going to a same wire or pin. So, to avoid the current to pass into each ...
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1answer
106 views

Solar panel strings: when does current flow via bypass diodes where each panel has a different maximum power point?

When having strings of 5 till 6 a-Si/µ-Si thin film PV panels and each panel its junction box is containing a BY255 by-pass diode, to make sure that current will flow in less optimal situations, like ...