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.
2,318
questions
0
votes
2answers
61 views
recovery time diodes
During the recovery time the voltage VF in a diode is positive but the current IF is in the opposite direction. I think it’s very confusing, since all the current are flowing from high potential to ...
1
vote
1answer
22 views
Alternate battery switching module
I am looking for an circuit that can do as follows.
I have DC24v (200A) x2 battery packs and 24v DC electrical equipments..(which uses about 80A atleast)
So lets say i want a circuit board that can ...
0
votes
1answer
57 views
Torchlight LEDs in series, is this possible?
I recently got hold of 2 broken LED torchlights and I had the idea of putting the LED heads together (after I cut them off) in series to make 2 lights for a camping powerbox that I want to make (LEDs ...
0
votes
3answers
79 views
I can't understand the function of this diode
On a past project, I've used the LM2576 buck converter with success. However, I've never understood how the catch diode works (D1 on the diagram).
The datasheet explains the importance of the diode, ...
0
votes
0answers
26 views
Odd Problem and Question [migrated]
I have had a problem that had stumped me consistently. I have a 2005 sebring that has been intermittently going into limp mode. I checked the code and it told me the tranny control module power relay ...
0
votes
1answer
50 views
Switching Devices
I am currently working on a project looking at research materials on low voltage but high current switching devices. Is there any technologies/research out there that are rated for high Amp low ...
0
votes
1answer
32 views
IR diode radiation spot area
How much is an IR diode radiation spot area?
I put some IR diodes (receiver and transmitter) in front of each other and I want each transmitter IR diode only radiates on its reciever and does'nt ...
0
votes
2answers
40 views
Two 24VDC Sources And Diodes
Please give me some advices for below schematic. Why is the need of bridge rectifier if both sources are at the same voltage?
0
votes
2answers
59 views
What is the maximum frequency to use diodes for distortion?
What is the maximum frequency to use rectifier, Schottky or Zener diodes for cut off sin wave to square wave?
-3
votes
1answer
50 views
How to know the maximum input voltage a diode can handle
I would like to know the maximum input voltage a diode can handle, I am choosing diodes for circuit and i have noticed that datasheets of diodes such as the PMEG6020. Does not really say the maximum ...
0
votes
0answers
58 views
Would it be a problem if I used a larger diode
I have a malfunctioning electronic card and it seen that a diode was cracked on PCB. I do not have the same diode in my hand, I am trying to find an equivalent (cross referance). I have a diode which ...
0
votes
1answer
17 views
Diode and MOSFET SMT replacement
I am working on an Arduino project where am controlling a motor through one of the Arduino I/O pins. The motor has nothing special just a regular 3-5V motor.
In my circuit am using a diode and a N-...
0
votes
6answers
48 views
Feedback diode question
In the following circuit the explanation of D1 says:
“D1 connected across the input to output terminals is for protection and prevents the regulator from being reverse biased when the input supply ...
0
votes
0answers
95 views
Alternative for THT component with SMT
Am working on an arduino project where am controlling a motor through a I/O pin turning it ON and OFF, circuit below:
Now am trying to make a PCB out of this circuit, to do so i wanted to switch ...
0
votes
0answers
25 views
Schottky diode EAS test circuit
I'd like to test the non-repetitive avalanche energy (EAS) of a particular Schottky diode (VS-12CWQ10FN-M3), but I've never done this test before and can't find a typical test circuit. This comes from ...
0
votes
2answers
67 views
Voltage across Zener diode is higher than the Zener voltage
I have this circuit:
Assuming that the knee current is 0.2 mA and that the Zener voltage at current 5 mA is 7V. I would like to find the voltage across the load. I am however confused with the ...
0
votes
0answers
66 views
8000 Amps across a 1 A diode for 0.2 uS
Assuming that the diode is rated for 20 kV and the pulse is only 250 V, will a 250 V 8 kA pulse that lasts 0.2 uS break a 20 kV 1 A diode? This also assumes that the diode recieves 10 of these pulses ...
1
vote
1answer
102 views
Why do we assume that V is zero?
In the photo below, under the diode (D2), we're given V and to help solve for current, V is equal to zero in the solution. How can we assume V=0 if it's not given in the question?
-5
votes
0answers
23 views
Design a variable control motor [closed]
The following material are give 1 5vac 2. 20vdc electric motor 3. Variable resistor 4. Connecting lead 5. Led 6 IN4001 freewheeling diode 7. 1000pf capacitor 8. Transistors . with dis component ...
1
vote
1answer
99 views
Why do some analog circuits use a FET with shorted drain and source?
Why do some analog circuits use a FET with shorted drain and source? Depending of the type of FET, it may either act as a capacitor or a diode? It each case, why not just use a cap or a diode?
Below ...
0
votes
1answer
25 views
Trying to understand how they got equation for Vzo
this might seem like an easy question but I'm still new to circuits and I'm trying to understand how they got the equation for voltage.
They have the solution as 6.8=Vzo+5m(20), but when I looked at ...
2
votes
2answers
2k views
Can you identify this DIODE or its logo?
Can you identify this diode or its logo? I'm hoping to at least learn who manufactured it to narrow my search.
1
vote
1answer
38 views
How to calculate the power rating of zener diode for flyback protection?
I'm trying to calculate the power rating for the zener diode I'm using on my circuit for flyback protection.
For example, if a flyback event occurs, the cathode of the zener diode is having a 30V ...
0
votes
2answers
77 views
How can I find a replacement LED to repair RJ45 tester? (re: SMD size, measured with multi-meter)
I'm trying to fix an RJ45 (CAT5/6 lan cable) tester and I need to replace some LEDs and diodes (SMD and not through-hole).
The tester has 8 LEDs (one for each wire) and only a few are blown so I ...
1
vote
1answer
73 views
DC current through diodes in AB amplifier
I can't figure out how the DC current through the diodes is calculated in eq. 8.22 on this PDF from University of North Carolina.
$$
I_D = \frac{V_{CC}/2-V_{BE}}{R_f+R_2}
$$
\$I_D\$ should be equal ...
0
votes
2answers
78 views
Intuitive way to think of transistor saturation current?
I am having a hard time understanding what saturation current (denoted Is in my textbook) actually means for a transistor.
For a diode, it makes perfect sense, it's the approximate maximum reverse ...
0
votes
0answers
51 views
How do we find where the average voltage resistor load formula came from?
Applying the half wave rectifier.
We have in series a source called \$V_{in} \$, a diode and the resistor load. To find the average resistor load we use this formula : \$(V_{max} - 0.7) / \pi \$
I ...
-2
votes
2answers
37 views
What are the assumptions or conditions to consider when there is a diode parallel in a circuit ( both forward biased)?
Both diodes are in forward state.Si=0.7 and GaAs = 1.2.
0
votes
1answer
63 views
how to let dc only go one way
I'm planning to make a circuit that lets me switch my keyboard and mouse between 2 computers.
this shows me how to do it.
https://hackaday.com/2016/11/12/diy-kvm-switch-lets-you-use-one-keyboard-and-...
-1
votes
1answer
98 views
Problem in understanding transistor
I am high school student we are doing transistor in our class but I could'n understand the topic, I have read several answer on site both physics as well as electrical engineering stack exchange ...
0
votes
2answers
105 views
What is this Diode for?
This part of a schematic from the I/O board in the link below shows a 1N4148 diode in parallel with an optocoupler's input circuitry.
What is this diode for?
https://startingelectronics.org/projects/...
23
votes
7answers
11k views
Basic diode question about voltage-drop
We have been begun studying diodes in electronics 1 and I have really basic question that may be really dumb but I cannot find an answer online.
If a diode is in series with a resistor and a voltage ...
0
votes
2answers
48 views
nmos reverse current protection
Let's assume I have a voltage sources V-A (like Arduino) and V-C (like Computer) and there is a load R-B (like some bidirectional thing) in between. I want to power up the R-B from either voltage ...
0
votes
4answers
45 views
Estimating current when voltage drops > voltage input
Let's say I have a circuit with a 5V battery and a 2V LED and a 100 ohm resistor. Ignoring certain properties of an LED, I can estimate the current by doing:
...
1
vote
2answers
48 views
Solving for current with voltage drops
Given the following circuit:
Why is the current through the circuit 34.7mA instead of 35 mA? My thinking was that:
The LED draws two volts, so it effectively makes the battery 7V instead of 9V.
...
0
votes
3answers
126 views
How to calculate Resistor needed in PNP Transistor Circuit
I am trying to calculate the resistor value I need to achieve 35mA in my circuit. Vcc is 5V. Can someone explain the values I need to find in the datasheet as well as formula to use to find the ...
0
votes
0answers
30 views
Is PMEG4005CT applicable here?
I am attempting to diode-or two power supplies (5V and 12-16V) and PMEG4005CT looks correct. Can I connect 12V to A1 and 5V to A2, have them isolated from the other's voltages and power the system ...
0
votes
2answers
64 views
Finding value of resistor between two diodes [closed]
I'm using an Arduino and I have the following circuit:
I couldn't find the symbol for analog signal, so the voltmeter represents a connection to the Arduino's analog input pin.
How can I work out ...
-1
votes
1answer
81 views
Small glass component with three colored stripes:yellow,green,and orange.The center of the component is a small cylinder
Small glass component with a tiny cylindrical structure inside the glass packaging.The colored stripes cover it up.
2
votes
1answer
89 views
MOSFET Fails After Few Uses
I am attempting to use a N-Channel Logic Level MOSFET as a switch for a phone charger that runs on a 42V battery.
I have a resistor circuit with an LDR that currently outputs 3.3v when LIT with a ...
0
votes
0answers
15 views
2 switch forward converter oscillation simulation
Here is the simulation of a 2 switches forward converter :
The blue waveform is the voltage across the inductance. It seems that there is an RLC circuit. R is really low, which is why the ...
-1
votes
1answer
34 views
Full wave bridge circuit voltage calculator
A transformer with a 12.6 Vrms secondary supplies the AC voltage for a full-wave bridge circuit. The output goes to a 1000 microfarad capacitor in parallel with a 4.7 kilo ohm resistive load.
Compute ...
0
votes
1answer
38 views
How can I connect a 24v-powered inductive proximity sensor to a 3D printer control board?
I am attempting to connect an inductive proximity sensor to my 3D printer. The sensor I'm using is a Zhongde PL-08N2 sensor, which is an NPN output NC (Normally Closed) sensor. As I understand it, ...
1
vote
2answers
73 views
Flyback Diode for 24V DC Solenoid
I am trying to select a diode to prevent my circuit from being damaged by the collapsing magnetic field from the solenoid in my circuit. Solenoid power will be switched off through the actuation of ...
0
votes
1answer
42 views
What is the use of the diode connected anti parallel to the gate resistance in the general MOSFET/IGBT gate driver circuit?
From my limited knowledge, the only advantage of providing a parallel path through diode with a lower resistance across the main gate resistance is the high speed turn off of the power electronic ...
5
votes
4answers
13k views
Why does current change when adding in an LED?
In the following diagram:
The current is 1 mA from:
V = IR
R = 1 / 1000 = 1 mA
However, when I add in an LED with forward voltage 1V:
Why does adding in the ...
0
votes
2answers
74 views
Dual Coil Latching Relay with LEDs - Opposite LED Triggers on Trailing Edge
This is my first time using dual-coil latching relays (Kemet EC2-5TNU), and I'm running into some strangeness when breadboarding out the below circuit:
The coils switch without issue when sending a ...
0
votes
1answer
67 views
Trouble understanding limiter circuit with diodes
I have a problem. I have this circuit:
I'm told that this is a limiter circuit. The question goes exactly like this:
"Assuming the diodes are silicon diodes (0.6V voltage drop needed in forward ...
0
votes
1answer
46 views
Diode marking code KE OB, what could that diode be?
I need the datasheet of this diode. The code written is KE OB or could be KE 0B.
16
votes
1answer
2k views
What are the various 'properties' of a diode?
I have come across various properties of a diode, phrased differently in different places (product sheet, everycircuit, etc.). For example:
The wavelength is the simplest and that is the color of ...
