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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LiFePO4 auxilliary for a hybrid car?

Hybrid electric vehicles use 12 V for most purposes (other than traction and aircon), and they generally come with a 12 V ‘auxiliary’ battery (lead-acid, about 45 Ah) charged from the vehicle DC-DC ...
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21 views

Thermal voltage of Ge diode

What is the thermal voltage of a Ge diode?I know for a silicon diode is about 26mV at room temperature. I have this circuit: simulate this circuit – Schematic created using CircuitLab and a set ...
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37 views

Analysing diode and resistor circuit

I'm trying to analysis circuit with parallel circuit of diode and resistor. the diode is ideal diode with forward voltage of 0.8V, and I'm trying to calculate voltage across D2 and R2 (V_out) For ...
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59 views

Circuits with diodes shockley equation

I am using the Shockley model to evaluate the current through a diode and the voltage across it and I have this circuit and this is where I am stuck: simulate this circuit – Schematic created ...
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3answers
128 views

I can't get a through hole diode to work on mechanical keyboard PCB key

I'm not experienced in electronics or soldering. I find myself soldering the components of a PCB from a mechanical keyboard, all right and smoothly, except for two keys. When I use the multimeter in <...
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1answer
55 views

Formula of ideal diode for dc load line analysis

There is a formula when solving diode circuits with load line analysis which is not the Shockley diode equation but looks like it and it is exponential this is what i can remember about it I am ...
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1answer
80 views

What is the exact meaning of 0.7V voltage drop in a forward-biased diode?

this question is partially (but not totally) discussed here: Why do diodes have a voltage drop? Does the power drop on a diode become entirely heat? The conclusion is that, in a forward-biased diode ...
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1answer
44 views

How to determine the ideality factor (N) of a diode from the datasheet?

I have to find Is an N from the datasheet of diodes 1N4004 and 1N4148. I did this by estimating both of these by accomodating a straight line in the log-linear Id vs Vd graph in the datasheet of each ...
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46 views

Understanding a diode's power rating

I thought I found a suitable diode for a project I am working on, it has the correct current and voltage ratings, but then I noticed the power rating and now I am lost. The diode in question is the ...
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38 views

Help finding replacement for diode (F4)

i do need to replace a diode that fell off / got lost on a circuit board. I do have an identical element that i used to take pictures. The diode in question is the one on the right, marked "F4&...
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38 views

Selecting proper bypass diodes for solar panel

On my sailing boat we've installed four solar panels (two times Vmp = 17.64V, Voc = 21.6V, Imp = 5.67A, Ioc = 6.07A, Pmax = 100W and two times the same but 75W), which we connect all in parallel, then ...
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37 views

How does ground affect a circuit with a diode, connected to the power source which is connected to a ground and an LED for it to act like a NOT gate?

I was searching for a way to use diodes to make a NOT gate. I found a circuit online and simulated it in an application. The configuration has a battery (1),where the negative terminal is connected to ...
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1answer
93 views

ESD protection diode required for 1.8V processor pin

I need ESD diode protection for 1.8V processor pin and its absolute max. voltage is 2V. I searched various parts but not available in this 1.8V of ESD protection. So does anyone use the same kind of ...
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47 views

SCR vs diode VI characteristics

We know in an SCR when in conduction mode, triggered by some gate voltage, the lower three junctions will essentially turn into a single N junction and so the SCR essentially becomes a PN junction ...
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860 views

Diode and capacitor part of a circuit: I don't understand it

I'm fixing an electronic device (a Sony Discman D-50) but there is a part of the circuit that I don't fully understand. This is the part of the circuit I'm talking about. I've highlighted the part I'm ...
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118 views

Why does this opamp have a diode on v+

I was working on a layout for a guitar effect, and noticed on the schematic that 1 opamp has a 1N4148 diode on V+. IC6 on the schematic below. Given it has an internal power supply, I'm assuming ...
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38 views

unwanted time delay in latch-circuit with diode

I am trying to use the following circuit. It somehow does what I want, but I would like to a) get rid of the time delay. b) would like to understand, why the time delay gets that high (and also, why ...
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Trying to find this specific manufacturer for a diode

I am trying to find these specific diodes and who made it. Thanks for your time in advance. They could be tvs diodes also
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56 views

Ideal Components in Diode Clamp

I have a question regarding how diode clamps work in a ideal circuit. The voltage source with infinite output impedance will force Vout to 6V The diode will be forward biased with a vf of 0.6V. Thus ...
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107 views

How does this simple circuit work?

I'm trying to create a project but I'm stuck somewhere. I decided to put a small portion into a simulator and it seems like the MOSFET is able to turn on and electrons can flow from the second diode. ...
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1answer
127 views

Diode forward current with µV..mV forward bias

When running LTSpice simulations on forward biased diodes I get plots like the following: This example is for a BAS116 and a 1N4001 - the current in the sub mV region is about 5 orders of magnitude ...
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2answers
38 views

Input impedances in CB and CE transistor circuits

Considering the input signal being placed across the Emitter-Base junction directly in both circuits(Common base and Common emitter), and considering this junction similar to a normal forward biased ...
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32 views

Energy Harvesting Circuit Utilizing MOSFET Based Bridge Rectifier

I really need help, I am working with an AC/DC semi-active boost rectifier, I replaced the two diodes on the high side with N-channel depletion-mode MOSFETs as an ideal diode that can lower power ...
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2answers
49 views

Trying to understand negative voltage generation with capacitors and diodes

I want to generate a negative voltage from a possitive rail. To do so, I'm reading this article. Here is the schematics it is depicting, assument the input step is +10V: I understand that when the ...
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99 views

Zener Diodes: How are different voltage drops achieved

How do semiconductor makers make zener diodes with a fairly wide range of voltage drops? In particular I'm curious how they get small increments - 3.3V, 3.6V 3.9V, 4.2V, 4.8V etc as I thought the ...
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91 views

Can I use a resistor with higher resistance?

I'm very new to electronics and wanted to use a couple of led diodes, I used an online calculator and it says I need a 40-ohm resistor, my question is can I use a 100-ohm resistor instead of 50? what ...
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103 views

LED open and short detection

Can someone tell me on what how to detect a short circuit and LED open circuit for the below circuit? Is it possible to detect which LED? Could someone provide a circuit which would help to detect an ...
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2answers
48 views

How to attach wires on a keyboard controller PCB

I want to make a module with 3 momentary buttons that will be record the numbers of pushes on a pc. For this first i though about using an arduino but also I am trying to use a keyboard motherboard/ ...
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1answer
57 views

CCM, DCM and BCM - Inductor

In a boost converter, what is the factor that determines whether the power supply (dc-dc converter) will be in the CCM, BCM or DCM mode? Because, I have an LED Driver A80604. And I am trying to ...
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24 views

LTspice peak detector analysis: Time step too small

I made a peak detector with a test file in LTspice. Here is the diagram: When running the test file, I ran into this an error message: Time step too small; time = 0.011, timestep = 1.26068e-017: ...
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40 views

Boost converter inductor selection - inductor ripple current calculation based on input current or output current?

I've a question regarding the inductor selection in a boost converter. In this TI App note under Inductor Selection on page 3, it is asking to assume the inductor ripple current as a percentage of ...
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1answer
51 views

Full bridge rectifier - in depth explanation

Most explanations of full wave bridge rectifiers start off with a diagram like the one below, and then go on about what will happen on the positive and negative cycle of the AC input voltage. This is ...
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2answers
46 views

Confused about photodiode current

I am confused about the photodiode current voltage diagram. According to this diagram the current at zero bias is down->reverse current.How is that even possible? At photovoltaic mode isnt the ...
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1answer
62 views

An OR power supply circuit

consider the following circuit: This image shows a simple "diode OR" power supply switch. I am trying to derive the cheapest circuit to obtain this functionality (the given circuit does not ...
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1answer
59 views

SMD diode identifying marking

I need help to identify this diode, mark "AC C" I attach photos of it I think there are SOD123.The caliper said 3,2x1,64 This is how they are in the PCB. They are connected in this way.
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536 views

How can a diode parallel to the source can't take the source value but take about 0.7V?

I was practicing diode circuits and this question stucked in my mind. When a diode connected parallel to a DC voltage source, doesn't it have to take the value of the source rather than 0.7V according ...
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2answers
50 views

Understanding Power Diodes and Heatsinks

I am working on reverse engineering and understanding a circuit board from the 1970s. I don't have a schematic diagram from the manufacturer. This board has an unmarked power diode that has a flange ...
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2answers
50 views

Phase shift in AC Circuit power calculation

I have the below question. I am not trying to ask the answer for the problem. But my question is that, we can see that 60deg is the phase shift. But both the voltage and current across the passive ...
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2answers
83 views

Arduino spuriously resets with power draw

I have a simple circuit, pictured below, that uses an Arduino to control two large bidirectional motors via 12V relays. Normally this works a treat, but sometimes the Arduino ends up resetting itself. ...
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1answer
61 views

Part Identification, Board says C32 but it looks nothing like a capacitor and has 6/9 marking on it

First, I understand that you have to remove the components to fault find but this is just something to play with. It's an internal HDD SATA adapter to USB3 with additional 12VDC for 3.5" HDDS. It ...
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3answers
509 views

Recovery of transistor wired as diode

It's a simple question. What's the turn-off time of this "diode" and does it have a recovery time when turning off? Since the transistor does not get into saturation I think it should be the ...
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0answers
55 views

Identifying a Diode

I am trying to work out what diode this is. I can tell that the red spot indicates the cathode. If I use the standard color scheme for resistors I get 0904 (or 904 if the first black band is not ...
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41 views

How can i make the pulse at V2 shift by 180 degrees in order to make it a negative 7.2 symbol for H bridge motor

This is the circuit I built in Lt spice. The NMOSFETS I downloaded online have 1,2,3 automatically i cant change the label. 1= drain, 2 = gate, 3= source. This is the result i get However i need to ...
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37 views

Identifying smd diode

Having a hard long time identying an smd diode, the code on it is: L F3 No access to the board datasheet. It's a xenon ballast board. Dimensions meassured: 2.3mm (length) x 1.4mm (width)
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24 views

ADC Clamping Rrotection Circuit with Dual serial Diodes - Formula proof

I am trying to undestand and calculate why in the first circuit we measure 5.7Volt (if forward noltage diode is 0.7Volt) and not 12V. I used the Superposition Theorem which first I replaced the Vcc ...
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3answers
61 views

Calculate diode voltage drop

I have studied the diode model which treats diode like elements with constant voltage drop and depending on the bias of the diode the voltage drop varies. Now I'm starting to learn about the correct ...
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1answer
69 views

IGBT not switching on with a diode in connection

Hi, I am trying to switch on/off a IGBT (CM1000HA-28H) to control a current. The IGBT is driven by a driver board (Powerex BG1A board). A problem we encounter is that if a diode (SD600) is connected ...
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2answers
127 views

Backward diodes VI curve

I am searching for the IV curve of a backward diode but couldn't find anything, any help?
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1answer
47 views

Tunnel diodes Zener breakdown

Do tunnel diodes exhibit Zener breakdown? Since tunnel diodes are more doped than Zener diodes they should, but I am unsure.
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4answers
138 views

Design of electronic lock

I am designing a electronic lock using a electromagnet(coil).This is my circuit: simulate this circuit – Schematic created using CircuitLab When the switch is closed it will short the circuit ...

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