diode? Answered

Can  i use several diodes in4007 alike to lower the PSU voltage to say 3vdc  from 5vdc to power a radio? also can I do the same to build a laptop psu just to charge out of a lcd psu gives 25v DV , can I use drop voltage bu using same diodes since each one 0.7v drop? thanks Al

Question by celalboz   |  last reply


zener diodes????????????? Answered

I know that Zener diodes will only let pass a given voltage.Say for example a 3 volt zener diode lets pass 3 volts or higher only(not below).But recently I came across an instructable where a zener diode lets pass voltage when it falls below a range.Back to the 3 volt diode,it allows voltage to flow through it only when its below 3 volts.But how??are they different types of diodes.Please give me a brief idea to clarify my doubts.Hope you get my question

Question by Adarsh_tronix   |  last reply


diode change

I'm building a picmicro programmer, and I'm fcollowing the schematics from this from sparkfunhttp://www.olimex.com/dev/images/pic-pg2c-sch.gifthey want a BZV55C5V1 diode, but the closest thing that I could find on mouser was a BZX55C5V1 diodehere's the link for the BZV55C5V1 datasheet, just click one, they're all the samehttp://www.datasheetcatalog.com/datasheets_pdf/B/Z/V/5/BZV55C5V1.shtmlhere's the link for the BZX55C5V1 datasheethttp://www.fairchildsemi.com/ds/BZ/BZX55C5V1.pdfPROBLEM SOLVED THANKS TO THE CITIZENS OF INSTRUCTABLES

Topic by guyfrom7up   |  last reply


Type of diode

Hey everyone, I recently had an ASUS laptop to repair and after troubleshooting, found some damaged components among which is this surface mount diode (kindly see picture). I looked around for a datasheet but cannot find anything. Am also unable to find out exactly what type of diode it is from its code marking. I've had results varying from a 'leakage diode' to '3.3V zener diode'. However, I am suspecting it might be a schottky diode since it was in what looks like a boost circuit. Any help would be greatly appreciated. Code marking: 100 98FP1  j Thanking everyone in anticipation. Kind Regards, Nawaz

Topic by Nawaz   |  last reply


Diode question

I need help with diode. Actually a question: if you put diodes in series for example 2 diodes of 300 V will they act as one diode of 600 V?

Topic by Dantex   |  last reply


Laser diode

I need a laser diode from 18x or more dvd writer or blue-ray writer.please help me.I dont have a credit card to buy them from e-bay

Topic by Rhsameera   |  last reply


diode logic

I'm making a giant adding machine using only resistors(miscellaneous), switches SPST (for input) LEDs (for display) and diodes(for logic). NO TRANSISTORS I have it so that it can recognize 0,1,2,3,4,5,6,7,8,9, but if it recognizes 8, then it recognizes it as all the other numbers. If it recognizes 0, it recognize 1, and 7. If it recognizes 6 it recognizes 1, and 5. If it recognize 9 it also recognize 7. If it recognizes 3, it also recognizes 7. basically if you take a 7 segment display, any number on it, it'll recognize all the numbers in the number. I need help sorting it ou so that if it recognizes 8, it only recognizes 8. If it recognizes 3, it only recognizes 3. Etc...

Topic by guyfrom7up   |  last reply


Diode Help

Hi, i have a bunch of diodes laying around, can somebody explain the diode function on multimeter? sure, there's numbers on the multimeter, but what do they mean? maybe give me a formula? Thank You!

Topic by Sandisk1duo   |  last reply


Zener diode. Answered

What is the voltage drop across a 3v, 0.5W Zener diode?

Question by Ahtasham Ahmad Mohtashim   |  last reply


Rectifier Diodes

My friend took apart his broken Kenwood amplifier. He used his multimeter to find the broken part,  then removed the RM4Z rectifier diode. I've been searching for about an hour, but I cannot find any websites that sell the RM4Z diode. The closest I have found was one from Hitachi, but I read that the RM4Z was from a Chinese company. Suggestions?

Topic by freethetech   |  last reply


Laser Diodes? Answered

 So, I have 2 laser diodes, but I don't know what the voltage/amperage/wattage on them is. Anybody know how I could figure this out?

Question by iBurn   |  last reply


What is the type of this Diode?

Hi,all Please help me with a specific type of diode unidentified.it's symble is like a zener diode or Schottky diode.

Question by gada888   |  last reply


Reversed Bias Diodes?

I really want  some clarity on "reversed bias diodes" whats the point of having a reversed bias diode? when would a person want to apply it to a circuit? if current can't flow through it, wouldnt it just mess up the circuit? Please shed some clarity on this subject for me, it would be greatly appreciated! -Grizzly

Topic by Grizzly_Bear   |  last reply


tunnel diode,s

Can you tell me a place that sells tunnel diode,s? I found one tunnel diode in a jvc radio but I lost it.:-( can you tell me the best free schematic drawing programs for Win XP,also.Thanks

Topic by maker12   |  last reply


red laser diode

Http://www.metacafe.com/watch/948616/how_to_build_a_high_powered_burning_laser_pointer/can anyone send me the link or what i have to do to buy this diode as this young man did David

Topic by Dystonia   |  last reply


Diode Calculator will not work

I've been working on a diode only (well, plus switches for input [numbers, yet there's only one pad! not one for each digit], resistors for various things, and LEDs for the display) calculator that could add two two digit numbers (xx+xx=xxx) for a while, putting countless hours into it.I have deemed it impossible.There's so many problems with a mass diode resistor network that is just won't work. As some and gates conduct then some other gate (like it's suppose to) conducts, and eventually causes a voltage divder (with the pull up/ pull down resistors) and the output gets wacky and there's no wway of amplifying the signal.The diode adder is dead

Topic by guyfrom7up   |  last reply


Laser pointer diode

I was making a laser trip wire, but I was looking online for diodes which I found, by which one would be best to get, I dont care for the color, in fact I am better off with red and the intensity can not put off heat to harm anyone. Anyone have any laser diode recommendations or have a site that I can buy them from?

Topic by bprins   |  last reply


"Shunt" diodes with resistors? Answered

I'm making diode bridges to have a nice supply of DC. I'm making a high voltage bridge for a 7.5kv nst and a low voltage bridge for regular 120v wall outlet . My high voltage bridge im going to make with several 1N4007 but i read that they should be "shunted" with 10Mohm resistors im not sure what is meant by this. Does it mean resistor, diode, resistor, diode or does it mean diode and resistor, diode and resistor. The pic says it better than i do.  Also, do i need resistors for a bridge for 120v bridge?, im going to use the diodes from a fluorescent light power supply.

Question by jaydenr   |  last reply


Help with zener diodes? Answered

I'm trying to get a better grasp on how to use a zener diode. I have plenty of information about what they do (allow current to flow one way until the voltage is high enough, then reverse the flow), how they work and even how they are made, but finding basic information about how to use it is harder. I am trying to connect a Keyboard Encoder to an Arduino. The Encoder runs on 3.5v and the Arduino runs on 5v. When a pin on the Encoder is connected to ground it outputs a keystroke to the computer. I have an Arduino pin set to HIGH (5v) as normal and under some conditions it changes briefly to LOW (ground) which is when I want the Encoder to output to the PC, and then back to HIGH (5v) again. To protect the encoder from the higher voltage coming from the Arduino I think I need to use a zener diode. If my understanding is correct it should work as described in the diagram. When the Arduino pin is High (5v) the Encoder reads as 3.5v and any voltage over 3.5v is drained to ground rather than pushing against the Encoder. No keystroke is passed. When the Arduino pin is LOW (0v) the Encoder reads 0v, the zener diode adds resistance and voltage runs to the Arduino. The Encoder sends a keystroke to the PC. My main concern is that once the voltage is over the 3.5v all of the power will drain to ground rather than maintaining the 3.5v before the zenner diode. I can't find anywhere which will tell me either way. If you need more information on my set up please let me know. I'm really struggling to get my head around this! Thanks!

Question by RandomIdeaMan   |  last reply


LEDS vs Diodes? Answered

I had a thought: Since LEDs are a form of diode, can LEDs be used instead of diodes with similar properties in a circuit?

Question by robotguy4   |  last reply


500 Glass Diodes

Selling 500 assorted glass diodes. To purchase go to "http://cgi.ebay.com/500-Assorted-Glass-Diode-/260660715619?pt=LH_DefaultDomain_0&hash;=item3cb096e063#ht_500wt_1154" Thanks

Topic by tinstructable 


Diode current ratings Answered

How can I determine the current rating of a diode  A forward current of 2 amps is needed and the reverse voltage is 12v                                                                hopefully   Gordon                                                                                                   Thank you

Question by GordonT3   |  last reply


Blocking Diode Recommendation

So I want to charge some rechargeable batteries with some solar cells I bought and I heard I should use a blocking diode to prevent the batteries from discharging at night. I have 3 6V, 50mA solar cells in parallel for a 6V, 150mA total. Does anyone have a recommendation for the model number or kind of diode I should use? Preferably one with a very low voltage drop. Or is my solar setup too small to require a diode? I have never done this sort of thing before, so any help would be greatly appreciated!

Topic by msh21   |  last reply


Diodes for Bridge Rectifier?

 Please Help! I need to make a bridge rectifier for a shake charging flashlight which also include using a 5V regulator - so it won't be a very high voltage, if that matters.  What type of diodes do I need for this bridge rectifier?  HELP!  thank you! patti :)

Question by mckywer   |  last reply


Laser diode driver? Answered

Dear all.. I would like to use this circuit (please see photo) for driver a laser diode to  engraving wood  -Item Name:ML101U29-25 (Mitsubishi) Power output: CW 300mW Pulse Power: 400mW Working Current: <340mA Working Voltage:2.2-3.0V  I know about this formula I = V/R But in this circuit I am not sure for calculate current .So please could you help me to know how many (mil.amp) I must setting for 9 volts power with maximum output 300mW (with safe laser diode ). -Or you show me other best circuit Many thank you.

Question by lam   |  last reply


Mosfets and zener diodes?

Backstory: I'm in the middle of modifying an ac welder to dc and plan on doing my first ibble using it as the topic.   Sorry for writing a book here,  I didn't want to be too vague and just confuse everyone.  I have most of the parts for the DC power supply,  I'll be using a bridge rectifier,  and LC filter consisting of 4x22000uF 63v caps, and a self wrapped torroid inductor.  It'll also have a bleeder resistor if some undetermined resistance. I'll be adding the rectifier to the secondary output,  and adding the caps in parallel with the gun and work leads,  and adding the inductor to the work lead.  It occurred to me today that by making this mod,  the gun tip will be hot for some time until the caps are drained by the resistor.  It's not the end of the world,  but I'd like to see if I can figure out a way to mitigate it with your help.  In its current state,  the trigger on the gun closes a circuit which contains a relay.   That relay closes the circuit on the primary coil of the main transformer,  and starts producing the stepped down ac voltage for welding..  I want to do 3 things: 1. Initiate a short across the relay supply to the relay drain and closing the transformer circuit until the caps reach a certain voltage. (Nice to have but not critical) 2. Insert a switch between the caps and the gun, it should be closed when the relay is closed (must have) 3. If I can get both of those working,  I can have the bleeder resistor on an open circuit while the welder is on,  and close it when is turned off to start bleeding the caps. I think all three of these can be done with some combination of resistors and transistors.  For the cold tip,  can I use a mosfet?  FDP030N06-ND looks pretty close. The ac supply is 38v 60A(low) or 19v 120a(high), I expect the dc to be close.   The caps I have are 63v though.  Will the extra few volts burn out the transistor since it's only rated for 60v? I know nothing about zener diodes,  but was reading that they should be used to protect the mosfet from back voltage caused by induction in the circuit. How do I size it? For charging the caps,  I believe I can tap the main power to a transistor which classes a circuit bridging the -/+ of the caps, with a resistor to only allow voltage to pass once it reaches a certain potential. If there is enough voltage it would trigger the gate on a transistor and close the short across the transformer relay.  Would this work,  am I over simplify ing it? Last,  to drain the caps when power is off,  I think I can use a transistor to be open while the main power is on,  and close when the power is shut off, letting the bleed resistor is doing is job.   Do they work like this?  What type would it be that is normally closed,  and opened when the gate is powered?  I'll see if I can create a circuit diagram and attach tomorrow,  but please bear with me,  I'm a total noob to electronics, it may be pretty bad.   

Question by DonaldF9   |  last reply


Does a zener diode work the same as a rectifying diode? Answered

I am making a solar charger and I can only find zener diodes and the voltage and amps I need, do they work the same as a rectifying diode? Thank You!

Question by JaredsProjects   |  last reply



What is zener diode? Can someone send me picture of it?

I need to know about zener diode to make my emergency light. So give complete description of it with a picture.

Question by bishal   |  last reply


Which type of diode for 12v 10amp to 12v 0 amp?

Hi all, wondering if you can offer any advice, I'm making a circuit that has two sub circuits:- circuit 1 10 amp transformer, connected to lights circuit 2 6 amp transformer, connected to lights Both these sub circuits will be bridged to  a large circuit , however  I believe I need a diode that will stops the 6 amp transformer getting to circuit 1, but the transformer from circuit 1 to power the lights in circuit 2. If this is correct could someone advise that type of diode I would need to drop the amps to 0. I'm not sure how diodes work however I'm using led lighting that will run off 5v so I'm aiming to have as close to a one way valve for power. Also will I have to place a diode on both the positive and negative or will one surface? Thanks for any help you can offer

Question by C2L   |  last reply


Solar panel diode and battery ? Answered

Hello, I have 5V solar panel which will charge my 18650 3400mah Panasonic 3.7V battery. I will use Voltage step up to 5V and I don't know which diode should I use between panel battery? I have all these diodes. IN4148 Diodes IN4007 Diodes  IN5819 Diodes IN5399 Diodes  FR107 Diodes  FR207 Diodes IN5408 Diodes IN5822 Diodes

Question by muratm7   |  last reply


Laser scanner laser diode

Can I extract a laser diode from a scanner. If so will it be as strong a if I got one from a DVD burner/player?

Topic by laserblast 


Help me read this diode!

Hey guys, I just tested a few diodes and they all seem to be blown (reading 5Mega Ohms in forward bias direction) I was able to find the part numbers for all but one. The one in question only shows the following on it: "4.3A  3A" The 4.3A is in slightly larger font than the 3A Does anyone have any idea what this could mean? This one gives me NO resistance value at all. Any help would be appreciated. Thanks!

Topic by daveman2010   |  last reply


Diode recovery time question? Answered

Hello, I have a little question about regular diodes. I know that when we connect a high frequency signal to a diode (in series with a resistor), that diode won't fully cut off the current as soon as the voltage becomes negative. (see picture) But what happens if we're not working on high frequencies, but we do create the same negative flank like in the picture? (so just the same as half the cycle of that high frequency signal, but we only do it once?) will the diode still have that same recovery time if the signal goes from positive to negative Very quickly? if that is so, that means that every regular diode fails at blocking a negative voltage pulse? Greetings, Electorials

Question by DELETED_Electorials   |  last reply


Do I need a diode? Answered

I am wiring 8x 5 mw lasers in parallel, powered by a 3.7v Li-Ion rechargeable battery. I was told that I would need a diode, specifically a 1n4001 diode to regulate polarity. I know what a diode does in theory (control the direction of electron flow), but I'm not 100% where in the circuit the diode needs to go. I'm assuming it goes between the positive battery lead and the output devices. Can someone clarify?

Question by h4xs4w   |  last reply


Determining values for zener diode

Hi guys, I am quite noob in electronics. I would like to know how to determine resistors and zener diodes values for a battery life indicator similar to this :https://www.instructables.com/id/9v-battery-status-indicator-circuit/ And if I want to use a battery source of 1.5V, how will the values change? Thanks!

Topic by kurtselva   |  last reply


Laser diode driver question

I'm planning on building an on building an IR light source for a DIY night vision setup. to do thus I'm using a 300 mw IR laser diode. the diode needs to be powered by 2.2 volts. I'll be using a LM317T to adjust to voltage but my question lies in the current needed. I'm familiar with powering LED's but not with diodes. since the power is 300 mw and the voltage is 2.2 V would i be powering it using about 130 mA? in addition to that how would I achieve this? I know the LM317 can be used as a current regulator but how is this done? any help would be appreciated, thanks.

Question by senortaco   |  last reply


Problems with Laser Module Diode

So I have a 5mw laser diode module that I am trying to get open so that I can install a 250 mw diode in its place. Problem is, the diode won't come out, the manufacturer glued it in, and I keep buying new modules from different sellers only to find inexplicably the stupid diode backing slathered in glue. Is there a way of getting this thing out? I don't care if the diode is broken, I don't need it, but I want the driver intact.

Topic by thedonquixotic   |  last reply


Diode laser cutting capabilities??

Hey guys, Im starting to build a 2 axis CNC for a laser. I was going to try the DVD burner laser and just cut through some paper for now but im wondering what the capabilities of the higher wattage lasers are. I know there are several 1-2+ watt lasers on ebay, what could they mange to cut through? Could I cleanly cut cardboard? What about vinyl for making stuff like decals and stickers? Im wondering if spending the extra money on a better laser would be beneficial or not so if anyone has some good comparisons or ideas let me know. Im on a tight budget for this build so a co2 laser is WAY out of the question. This is my first CNC build so its mainly to learn but the more capabilities of the CNC the better.

Topic by jdavis-9   |  last reply


Firmware for RAMPS without diode? Answered

HI. I have already lost an Arduino. So I want to remove the D1 diode in my RAMPS 1.4 to protect the Arduino Mega from over voltage.Can  I run the printer powering the arduino from my laptop's usb? Also do I need to change anything in the firmware for this? I am using the sprinter firmware. 

Question by SowmenD   |  last reply


Diode for world's smallest shocker

Does it matter what type of diode is used to make a small electric shocker because on the tutorial I found they use one from a camera but I'm just buying/using parts I already have 

Question by Divergence   |  last reply


Choosing the right zener diode? Answered

Hi Guys, I want to make a power bank kind of thing that can charge my laptop. Its not at all efficient and a powerbank or rechargable batteries would be better but its a challenge kinda thing. Due to my research I found out that zener diodes can not only prevent backflow but also limit the current. So I was wondering if you guys could help me choose a zener diode. I have attached a picture of the schematics. Please don't comment saying that its not efficient and stuff, I know that. ( Extra info: laptop requires 20 volts 2 amps) Thanks in advance :). -Prickly Potato

Question by The Prickly Potato   |  last reply


Zener diode Regulator Assy

I am in need of assitance for assembly instructions for building a 5V power supply from a 12v power supply using axial components. I am not sure of the orientation & solder method of components. Thanks for any help. MCD

Topic by mcoanarmen   |  last reply


PN Junction Diode Thermoelectric Generator?

Hi, I was wondering if you could DIY a thermoelectric generator by dissecting  some PN junction diodes and sandwiching the P type material adjacent to the N type materials between heat conductive material, such as two circuit board wafers?

Question by jmlidea   |  last reply


what diodes do i need? Answered

I made a litle schematic (picture is in paint) as an extra for my binary clock, since the wart is a litle bit to handy (i can reverse polarity) and i dont want to destroy my precious attiny2313, so i thought of of some diodes and made a plan. but, i had 4 zenerdiodes lying around, and i tried it, but nothing happened, the clock didnt power on. i think the diodes are to heavy, so i was wondering which ones i needed. its all in the scheme and i think its pretty obvious (i made it in paint, so the quality isnt good, as wel as my english :P)

Question by godofal   |  last reply



What kind of diode(s) do I need?

I am trying to make a device that uses a dynamo. (hand crank) The dynamo when cranking produces up to 12v which I want to use to charge a battery. The problem I'm having is that the current goes both ways. When I'm not cranking the dynamo, the battery turns the dynamo. I need to make the current only go one way, only towards the battery. From what I understand, I need a diode. The problem is, what kind of diode, and how do I wire it in my circuit? Any help would be much appreciated.?

Question by corsair130   |  last reply


I have a burned diode with no markings, can someone help me identify it? Answered

I checked the resistance with multimeter and it gives me 130 ohms both side and I checked it with diode checker and gives me 0.065 v on both side.

Question by hpcdr   |  last reply



Use of diodes when connecting solar panels in parallel?

I have a bunch of 24 volt 270 watt solar panels.  Eventually I'll be putting three in series, then combining the strings in parallel, but for a temporary measure, I want to just connect two in parallel.  I've been in tv repair for over 40 years so electrical theory doesn't confuse me, but solar systems are a different story.  I've used four smaller panels to run a car radio display at an old car show swap meet for the last 12 years, and I just ran them in parallel, then into the charge controller.  Now I'm reading about blocking diodes, and I understand what they're for and that some people use 'em and some don't. My question is, physically, where do you stick them, and related to this, what is the purpose of using a combiner box?  Is the box just to provide a weatherproof place to make the connections?  Are they used to provide the place to stick the diodes?  I see they have circuit breakers inside, and it appears there's one for each panel, or string of panels, but I don't see the point.  If a panel can generate 10 amps, you'd want a breaker bigger than that so it doesn't trip at full output, but what could trip it then?  You can't get more than 10 amps even if there is a short. This should be common sense, but since I don't have a combiner box yet to look at, can I assume if it's made to combine four panels or strings of panels, you can connect just two or three and save the unused ones for adding on later? Thanks bunches; caradiodoc

Question by caradiodoc   |  last reply