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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320 views

How to convert low voltage (< 0.4V) AC to DC

I've made a mini generator for a mini wind turbine. An oscilloscope voltage measurement shows a +0.4/-0.4 V sinusoidal AC current. I'd like to convert it into DC, in order to put a charge and detect ...
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2answers
73 views

Effect of LEDs in series instead of parallel with resistors

So I have two LEDs with a Forward Voltage rating of 2.65V each. Would I be okay in hooking them up to a power supply of 5v in series rather than in parallel with resistors? I'm asking mostly because ...
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1answer
124 views

Use a diode or a MOSFET with a backup battery?

I'm running off-grid 12V domestic electricity, with solar panels and leisure batteries. The charge controller sits between the batteries and the load, and occasionally, briefly, cuts out the load ...
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1answer
43 views

Why does the l293 have a higher current than the l293D?

I know the "D" mean diode, so it has a built in diode. I would not think that the addition of a built in diode would lower the current rating by that much. Also, if I were to use a l293, where would ...
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4answers
249 views

Why does temperature modify the characteristics of a diode?

Everyone knows that temperature affects every semiconductor device you can think of, and diodes are no exception. From the below graph, we can see that the temperature has marked effects on pn ...
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0answers
42 views

The equivalent circuit for \$V_{in} > 0\$ with the amplitude of \$V_{out}\$

I have a strong mathematical background and I am trying to improve my (poor) physics. If this is not the right stackexchange forum for this subject, I would be grateful if you could refer me to the ...
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1answer
32 views

Computing capacitor voltage through series connected diode

I have been trying to analyze this circuit and calculate the maximum voltage across the capacitor. Here is the diagram: And, here are the graphs for various inputs and the resultant outputs: ...
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3answers
133 views

Why the diode has higher impact on dc characteristics than ac?

Consider this circuit which consists of a DC bias and an AC source connected with a diode and resistor: Source: Boylestad and Nashley book 11th ed. Using superposition theorem the circuit was ...
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0answers
39 views

Single Transistor DC TO AC Circut

I have a question that may be rather difficult to ask and format however I will try. Now I am very new to electronics in general but in my spare time I play around with them a little bit. I have ...
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3answers
132 views

Why are two diodes used here?

I'm following the wiring diagram for a digitech fs3x guitar pedal footswitch. For the third SPST switch, it's wired from the other two switches connected by 2 diodes, both in the same direction. Can ...
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0answers
91 views

Modifiying SparkFun Uh-Oh Batt. Indicator - TL431 Regulator Diode Based

I'm trying to modify a simple SparkFun Uh-Oh Battery Level Indicator - KIT - 11087 https://www.sparkfun.com/products/11087 It can handle a maximum voltage of 12 or so volts, above that I believe it ...
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1answer
90 views

Do I really need a flyback diode when using a power mosfet?

I am using one of these IRF1404 Power Mosfet and looking at the datasheet I see that the continuous source current (in the Source-Drain ratings section) is rated at 202A!! I will be using it to drive ...
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0answers
33 views

Single sided capacitor discharge

What I am looking to do here is ,after current stops flowing through D1 , I want current for a few moments to operate the transistor . So this is the circuit , current charges up the capacitor and ...
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0answers
41 views

Strange diode identification [closed]

I am attemting to fix a tv (Samsung UN40EH5000F). On the power board, (Pd40AVF_CSM BN44-0496A PSLF760c04A) I know the the fuse is blown, but there is also a diode (DM804) that looks charred and ...
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2answers
47 views

Why doesn't the depletion zone cover the entire diode?

When you form a PN junction you're basically closing a circuit so why don't the free electrons in the N and the holes in the P diffuse completely as they would in any other circuit?
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2answers
60 views

Thermal Runaway in Diodes

Datasheet for 1N5406 diode states "3.0 ampere operation at Ta = 75°C with no thermal runaway". What does this mean exactly? Can I place these in parallel to increase current capability?
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2answers
30 views

Power and Ground Clamp Diodes in CMOS IO Buffer

I have usually seen Power & Ground Clamp diodes in CMOS structure as per attached figure. They are protection diodes. But I have few doubts :- 1.can someone explain in what situations they are ...
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0answers
33 views

Combining multiple solar chargers to increase output current?

Im looking to power an outdoor solar project that needs to power a 12v led light bulb @ 750 ma. I have a 12v step up regulator already, and was wondering if I could combine two of these inexpensive ...
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1answer
53 views

SMD diode value [closed]

I need to change surface-mount diode but i need to know its value. possible your assistance to know the value of the diode in the picture. what is the value of diode in picture? or how to get the ...
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1answer
89 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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0answers
30 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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0answers
64 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
44 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
24 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
82 views

What type of zener diode is this?

What type of zener diode is this? The thin band is blue.
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66 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
434 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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0answers
66 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
74 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
123 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
243 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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0answers
35 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
78 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
26 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
55 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
81 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
268 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
39 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
20 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
164 views

Diodes in Tachometer Circuit

How are the diodes helping in the attached ckt :-
3
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2answers
86 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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1answer
88 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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3answers
131 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
59 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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0answers
28 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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4answers
77 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
83 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
112 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 ...