Relay Logic

I have a fetish for antiquated technology. Stuff like vacuum tubes, transistors, electro mechanical devices, and of course relays used to run things. I did a few searches here on Instructables on relay logic and found nothing so I thought I'd start a forum on it.  Most of the earliest computers ran using relays. I love how they sound, clickity - clack. In a way they seem more alive to me than todays silent electronics, and dead boxes, There's just something cool about a machine that you can hear working instead of dead silence, maybe I'm just a old fashioned.  Anyway, I have a limited knowledge using relays for adders, if, and, or, gates, etc. but I'd like to learn more. I did however make a clock circuit using only relays and capacitors, and I have a video of it here... http://www.youtube.com/watch?v=Ya5R7EqF8vk I based that circuit (after lots of pondering and experimentation) on the clock in this relay computer here. http://www.youtube.com/watch?v=n3wPBcmSb2U My relay clock was really unstable and would stop by itself quite a bit. I'd like to figure out how to make it more stable. Also, I'd like to do some more experiments... Anybody else have any interest in this subject? Or have any experience making small bit relay computers, or relay control systems for robots, etc? By the way here's some other cool relay run computers and stuff. Another Relay computer http://www.youtube.com/watch?v=O-omFP_G57U&feature;=related Relay counter thing. http://www.youtube.com/watch?v=YQ4ynGxQnGY Mechanical pong game - run on relays http://cyberniklas.de/pongmechanik/indexen.html

Posted by bart245 8 years ago  |  last reply 8 years ago


simple logic circuit

Uuhhh..I'm not really sure about this..i'm an electronics engineering studentand my instructor in Logic Circuit and Switching Theory requires us to make a project which will include logic gates.now i searched in the net for some ideas i found two..but i know i shouldn't copy their projects..can anyone help me?link2link1thanks guys!

Posted by hazelcharisse 10 years ago  |  last reply 10 years ago


Control Logic with PWM? Answered

I am currently working on a robotics project, and need a bit of help. I have this H bridge, and would need to control it via PWM. Speed control isn't necessarily what i need, though i wouldn't mind. (In4 i should have just bought an ESC) The whole bot is controlled by PWM (All servos) except for the two DC motors that i have on it -- One for forward and backward, and another for rotating an arm. How would i control the H Bridge with PWM? Which pins would i connect what to? 

Asked by RocketPenguin 3 years ago  |  last reply 3 years ago


Logic Goats papercraft

Here is a super cute little project which I found unaccredited on 4chan (who'd have thought?)  Logic Goats!  Papercraft logic gates in the shape of goats, which nod their head when the appropriate inputs are given.  There are four (there may be others I haven't found): And-Goat Or-Goat Xor-Goat Not-Goat I haven't made any of them up but I plan to this weekend!  I'll post pix if I manage to do this :) Update: these are from a website called robives.com, which sells them; I've removed these copies as they're clearly pirated.  Thanks for pointing this out, meeze!  I couldn't find attribution on the PDFs themselves yesterday but on checking again today, one does have the url on it and they're all on the site for purchase (see links above). (Note about Internet safety.  There is an attack which is becoming more common, which can be embedded in PDFs using the Javascript capability in Adobe Reader.  I did a bit of research and I am confident that these Logic Goat PDFs don't contain any malicious code, but as with anything on the Internet, download at your own risk.  In general it is wise to disable Javascript in Adobe Reader, if you use that for PDF viewing.  There is an interesting discussion of one of these attacks here: http://isc.sans.org/diary.html?storyid=7867)

Posted by rachel 8 years ago  |  last reply 8 years ago


Turreted Logic Bow

Just an update for all of you guys, I have posted the mods to the Logic Bow to make it turreted. Mods can be found on step 6. If you haven't built it yet BUILD IT NOW!

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago


A New Gun by Logic Boy?

Hey guys If you haven't noticedyou will see that I haven't made anything new since my PP19, everything that I have made has either been an improvement to something else or I never got around to finishing it. well my creative slump is over. I recently got some new knex and I now have built a new gun *gasp* it is actually the full completion of an older concept of mine that worked really well but wasn't exactly what I wanted originally. So I now have a pretty awsoime new gun. Pictures will be posted this weekend. Until then try to guess what it is. Hint: I have posted the name of the gun somewhere Good luck.

Posted by Fred the Penguin 8 years ago  |  last reply 8 years ago


Knex logic bow review.

This is logic boys logic bow review. comfort: 10/10 - comfy handle and comfy grip. power: 10/10 - insanely powerful. looks: 8/10 - looks good. innovation: 9/10 - nice and small compacted firing system. accuracy: 10/10 - very accurate. piece usage: 9/10 - uses barely any pieces. stenght: 9/10 - the handle is a bit weak, nothing huge tho. reliabilty: 9/10 - if you have the pin taped up well, your good to go. overall: 74/80 - fantastic gun from logic boy, build it now!

Posted by ~KGB~ 9 years ago  |  last reply 9 years ago


Problems with logic(NAND) gates? Answered

I MADE a circuit that basically detects when an IR beam  is cut using a LM741 opamp .AS shown in the schematic i've connected the output of the opamp to the  two transistors (which is a nand gate) ,so when the beam is cut the output of the transistors should be high but instead the led at the collecter of the transistor glows only brighter. should i use a nand gate in a DIP package ?also when i individually measured the output of the opamp it showed that there was constantly 1.5 v coming out i tried measuring it with both opposite polarity leads of the multimeter  ,still  it showed a 1.5 v output,why does this  happen?PLS help.i need it fast.

Asked by Strontium 5 years ago  |  last reply 5 years ago


project

Can anyone help me give a simple project using logic gates...

Posted by ferdel 10 years ago


Logic breaks reality

My friend told me about this earlier today and I thought it was brilliant: Cheese has lots of holes. The more holes you have, the less cheese you have. The more cheese you have, the more holes you have. So logically, the more cheese you have, the less cheese you have. This got me thinking and I'd quite like to see if anybody has anything similar to this logic fail.

Posted by The Jamalam 8 years ago  |  last reply 8 years ago


Logic gate help

I'm attempting to build an binary calculator out of an old iphone box using LED's and such and have a wiring system set up but i need to know how to make/buy some form of "if then else" gate (i.e. if A=1 then B=1 else C=1 and if A=0 then B=0 and C=1). I would love to know if there is some kind of way to do this using transistor logic but anything that works as an "if then else" gate is welcome.

Posted by cdarcy 9 years ago  |  last reply 8 years ago


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...

Posted by guyfrom7up 10 years ago  |  last reply 7 years ago


Logic gate set up with basic principal of "A is I: B is I for 1 click, then O//A is O: B is I for 1 click, then O"?

I've been looking about for awhile now for a solution to this little puzzle I've managed to get myself into. I know the question may have failed to be a proper logical statement, but basically, this is what I need: When input a is on, output b will toggle on for one second, then toggle off. When input a then goes off, output b will then toggle on for one second, then off. Basically, when the input state changes, the output will go on for a second, then off. I know the opposite can be done (that is, one second input toggles a on output, or visa vers) with flip-flops, but doing this is a bit outside my realm. Any help would be fantastic! Thanks in advance!

Asked by DoctorWoo 6 years ago  |  last reply 6 years ago


Solve this logic puzzle if u can!

Here the puzzle:[img]http://img247.imageshack.us/img247/6384/newyearpuzzlecj7.gif[/img]Questions: Imagine that you have the layouts of 4 coloured cubes(ABOVE), named A, B, C and D. When the cubes are placed in (alphabetical) order in a straight line, and it is viewed from any horizontal or vertical position (front, back, top, bottom, left, right), there are always four different colours seen.Given that when I pick a corner of A, the 3 sides connected to it read "653", find the same orientation of B, C and D as 1 string of numbers. For example, "152421563".

Posted by bigmoney 11 years ago  |  last reply 11 years ago


Logic circuit to generate and convert 3 bits parallel binary code into series for subsequent transmission ? Answered

A project I am working on has 6 water sensors placed at different altitudes inside a tank.I've developed a circuit to assign 3 bit binary codes to each of the sensor and then transmit it wirelessly.I've attached the truth table and the binary functions that yield the desired output, as a picture.Please refer to it and check if it looks alright to you.Keep in mind that the sensors output '0' (ground) when idle and '1' (Positive) when active.  Also, the sensors are so placed that sensor 2 won't get activated unless sensor 1 is activated ,sensor 3 unless sensor 2 is activated and so on..I.e,when the sixth (last) sensor is activated ,all the other sensors would be active too.So,the truth table contains just the possible combinations. A,B,C,D,E and F are the sensors(bottom to top) X,Y and Z will be fed into a binary encoder ic,whose output will be transmitted. Surfing the web,I realised that logical high and low can also be set using pull up and pull down resistors .I would appreciate it if someone could enlighten me on how this is done.(Explaining with reference to my circuit will be the best way)

Asked by Adarsh_tronix 3 years ago  |  last reply 3 years ago


Logic Problems

I changed the topic name because I think so people might think of logic problems as a programming question or electronic question, so some people wouldn't bother looking at the topic. Think you're good at logic? Here are some problems: Title: Gorillas Enjoy Ballet Gorillas are the only animal that enjoys ballet. All animals can fly to mars. Scotch brooms bloom every Thursday all over mars. Only those few animals that do not play solitaire are immune to hay fever. No animal that travels in leaky rowboat ever has the penultimate word in a verbal discourse. Scotch broom in bloom is what gives animals hay fever. Those that do not handle hot ice cubes travel to town in leaky rowboats. All animals that have the penultimate word in a verbal discourse play solitaire. No animal that enjoys ballet handles hot ice cubes. What conclusion can you draw from the above information? Logic Puzzle number 2 This one takes up 2 pages, so I'm going to skip the story and say the logic parts. Basically this one guy thinks he smarter than gods or something so they give him a trial. He's trying to go toward the treasure and not die. Split in the road number 1, at least one sign is false, one path leads to a serpent. Path A: "This path leads to the serpent." Path B: "The sign at path A is true." Which way should he go? Split in the road number 2, 2 signs are true, one is false Path A: "The sign at Path B is true" Path B: "Path A is not the one to follow" Path C: "This is the Path to follow" Which way should he go? Split in the road number 3, 2 signs are true, one is false Path A: "Path B is the one to follow: Path B: "Path C is the one to follow, unless it's Path A" Path C: "Neither Path A nor B is the correct Path" Which way should he go? There are now 3 houses, one containing the treasure, there's a sign infront of each house. 2 signs are false, but one is true. House A: "C is not the house to enter unless THIS house is not the one to enter" House B: "The sign at house A is false" House C: "Either house A or house B is the one to enter" Which house should he choose? Please write your answer in the form of the path/house in order, for example ABCB would be path 1 is A, Path 2 is B, etcetcetc. On a totally different note (I don't wanna make another topic), can you use the cable that you use with a boarduino to make an avr programmer? If so, can you post an example schematic of how to hook up a chip.

Posted by guyfrom7up 10 years ago  |  last reply 10 years ago


Need help with state transition table and diagram

I need to make a sequential circuit which output will used for my combinational circuit input. I already made my combinational circuit which gives output in 7 segment display. I need to show EC1013 in & segment.The binary to show them is given below. 000=E 001=C 010=1 011=0 100=3 You can see I need to show EC1013 where 1 is repeated again..thats why I am unable to figure out the state  transition diagram for that... I tried to simply make the state transition table according to my output  and used K-map to minimize that and build that circuit..but it stucks in the 10 loop.. after showing EC10 it keeps on showing 10101010 forever.can some one help me with that

Asked by TanvirM1 3 years ago  |  last reply 3 years ago


What do i use for an "if then else" gate? Transistor logic instrucions would be best but anything that works is fine. Answered

What do i use for an "if then else" gate? Transistor logic instrucions would be best but anything that works is fine.

Asked by cdarcy 9 years ago  |  last reply 9 years ago


Einstein's Logic Puzzle That 98% of the World Population Can't Solve.

There are 5 houses each with a different color. Their owners, each with a unique heritage, drinks a certain type of beverage, smokes a certain brand of cigarette, and keep acertain variety of pet. None of the owners have the same pet, smoke the same brand of cigarette or drink the same beverage.The Brit lives in the red house.The Swede keeps dogs as pets.The Dane drinks tea.The green house is just to the left of the white house.The green house's owner drinks coffee.The person who smokes Pall Malls raises birds.The owner of the yellow house smokes Dunhill.The man living in the center house drinks milk.The Norwegian lives in the first house.The man who smokes Blends lives next to the one who keeps cats.The man who keeps a horse lives next to the man who smokes Dunhill.The owner who smokes Bluemasters also drinks beer.The German smokes Prince.The Norwegian lives next to the blue house.The man who smokes Blends has a neighbor who drinks water.Who owns the fish?You may now thank me for ruining your holiday.Here's what I have:Yellow-norwigian-DunhillBlue-horse-water-German?-Prince? Red-Brit-milk-BlendsGreen-Coffee-cats-German?-Prince?White-swede-Bluemasters-beer.I got the colors, and maybe a few other things, but it gets mucky after that. I think it is the Brit, but my friend says it's the German.

Posted by Spl1nt3rC3ll 11 years ago  |  last reply 10 years ago


Need suggestion in digital logic design semester project.

I need suggestion in digital logic design semester project,with use of gated ICs multiplexer etc.

Asked by szafar2 3 years ago  |  last reply 3 years ago


Oscillator with AND and NOT gates? Answered

Hi, I've been recently working with logic gates and that's when this struck me.If an AND gate and an inverter are hooked up as per the attached schematic, can point A function as an oscillator?Assume that the gate inputs float high. If so 1)What would be the frequencies of the oscillations if the gates used are a)CMOS b)TTL ? 2)Would the frequency change with the input voltage ? 3)Is this implemented elsewhere? Thank you for reading my question.

Asked by Adarsh_tronix 3 years ago  |  last reply 3 years ago


Dreams

I had a really weird dream last night about a guy in my class texting the teacher and getting his cellphone confiscated, so I decided to post this to see what weird dreams you have had

Posted by Fred the Penguin 9 years ago  |  last reply 7 years ago


Step selector displays wrong info

When you view any published instructable with multiple steps the step selector beside the PDF download button displays wrong info and behaves abnormal. This image shows I am currently on an intro page, yet the button is displaying step 2, which skips over step 1. Also clicking this button does not redirect you to the step. You actually have to double click it to get it to transfer you to the next step which would be step 2 instead of step 1 because of the bug. http://i.imgur.com/Ib9Q4PA.png This image shows me forcibly to step one and hovering over the arrow. It does in fact display the correct next page, and transfers you when you single click like it should. http://i.imgur.com/MsVN4Jk.png This image shows that everything is working like it should after the intro page. http://i.imgur.com/56HGgGm.png Overall this bug is simply a graphic/logic error bug on the intro page of all instructables which forwards you to step 2 instead of step 1 of the instructable. The standard next/previous buttons at the bottom of the page are not effected.

Posted by AbDuCt 5 years ago


Can someone provide the schematic for a 2 input TTL OR Gate with Totem Pole Output?

I have for some weeks been researching to find the schematic for a 2 input TTL OR Gate with Totem Pole Output (versus the Open Collector variety).  However, I have had little success in finding the schematic.  It was suggested that I try the Forum to resolve my problem.  Therefore, can someone either provide a reference that shows the schematic or draw one?  Thanks.

Asked by ElectroZapper 3 years ago  |  last reply 3 years ago


Levelshifting 3->5V. Can I add a DC bias of 0.5v or so to the 5v input line to bring up the 3v signals?

Assuming it doesn't just line up correctly, eg: If my Vih is 3.6v on the 5v side, and my Voh is 3.3v on the 3v side. By DC bias I mean connecting up a voltage divider giving 0.5v to the line connecting the 3v->5v. I'm guessing this isn't done as it would drain power when the 3v line goes low, but if the divider is high enough resistance, that could be minimal?

Asked by quatch 6 years ago  |  last reply 6 years ago


NPN to PNP control? Answered

So as I get into this project the circuit keeps building and now I once again have another problem that I can't figure out. As the title hopefully suggests I am using a NPN PN2222A trans. to control a PNP 2N3906 The idea was to use the 5v from a Ardinuo UNO to control a 12v. Currently I am testing with a 9v I had on hand. I thought it would pretty straight forward but every time I supply power to the NPN it creates the short needed to turn on the LED, but once I cut the power the LED stays on until I create another short (using a probe) uphill of the NPN. The only thing I can think of is that the LED doesn't the resistance needed for the power to re-saturated the PNP. Any thoughts? I will admit  haven't done any of the math needed yet for the resistors. Also can someone send me a link to the programs you use for drawing the layouts so I can move past MSpaint?

Asked by Jayccob 3 years ago  |  last reply 3 years ago


Would this work as an XOR logic gate? Answered

Hi, I'm new to logic gates and I am wondering if this would work as (or is) a XOR logic gate.

Asked by josh1324 7 years ago  |  last reply 7 years ago


Quote of The Week

Hey everyone! it's that time again Stereotypes are stereotypes for a reason -logic boy

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago


Logic signal conditioning question?

I a robot i am building, i need to condition the signal as follows with any Microcontroller, only logic gates If 1 is high then  A & C should be high If 2 is high then  B & D should be high If 3 is high then  A & D should be high If 4 is high then  B & C should be high Where 1,2,3&4 are inputs and A,B,C,D are outputs No two inputs will be high a t the same time

Asked by qwerty156 7 years ago  |  last reply 7 years ago


Quote of The Week

This weeks quote was used when a person said "in my opinion rock sucks"Everyone is entitled to an opinion, yours is just wrong.-logic boy

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago


Quote of the Week

Hi everybody! I will now be releasing a quote every week! this weeks quote: "Insurance, what Insurance? Oh you mean my shotgun?" logic boy

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago


Quote of The Week

As well as being on Instructables my quote of the week can also be found here as well as alot more awsome stuff When life gives you lemons, just be thankful you actually got something -logic boy

Posted by Fred the Penguin 9 years ago


Quote of The week

Well its monday so that means I can post annother quote, this week I am posting two: Life is much easier when you dont give a damn. Everything is possible, the Impossible just takes longer. -logic boy

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago


A Knex challenge from logic boy

Hey guys I got bored again, so here's a challenge. What I want you to do is build a motorbike from knex. It can be any colour and it can be built on any scale, but it cannot use any micro or exotic pieces. Closes 30 april. Winner will get the satisfaction of winning no other prizes unless someone offers a patch. I just want to see what you guys can come up with. I might even make something. Here is a picture of my motorbike.

Posted by Fred the Penguin 8 years ago  |  last reply 8 years ago


New Avatar

I am trying out a new avatar, do you like it or hate it? Should I go back to my old one?

Posted by Fred the Penguin 8 years ago  |  last reply 8 years ago


I Just got My 666th Comment

The title pretty much says it all =\ only 334 more until I get 1000 w00t!

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago


If you like Pearl Jam.....

Pearl Jam lovers get ready to be jealous, because..... I'M GOING TO PEARL JAM IN AUCKLAND ON FRIDAY!!!!!! thats all for now, If we get pics I'll post them here.

Posted by Fred the Penguin 9 years ago  |  last reply 7 years ago


Do you need antivirus software for PS3? Answered

I recently got a PS3 and I was wondering if I need to install some form of antivirus on it. It is a black slimline 120GB version just incase that makes any difference

Asked by Fred the Penguin 9 years ago  |  last reply 8 years ago


School

Readind the dj's cops suck topic made me think, alot of stuff happens at school, so this topic was born. What weird, funny or stupid stuff happens at your school. I dont want any specifics like names.

Posted by Fred the Penguin 9 years ago  |  last reply 8 years ago


New slingshot mech/trigger

I want to keep this brief whilst still remaining informitive, please excuse hurried typing hey guys been playing around with knex and found a mech that works. camera cable still lost, paint diagram below instead. to load band is attached to anchor at front, rod it then push/pulled through mech till trigger clickes into place, pulled further and rod is removed, ammo carefully placed back into mech (hollow back) trigger can then be pulled to fire. resultant gun is basicly silent, only one band can be used at a time. plans for a repeating version are still sitting around in my head. sorry for brief explanation, was kinda busy seeya later

Posted by Fred the Penguin 8 years ago  |  last reply 8 years ago


Cya l8r ppl

Hey guys. I just wanted to put a quick message out to all of you. I am leaving. To be honest I havn't been able to build anything major since the I bow, also my priorities have changed, it is getting to the buisiness end of the school year here so free time is at a premium. I also have my new guitar, facebook, youtube and modern warfare 2 all fighting for my attention. I will be leaving the site and knex for the forseeable future effective immediately (not like mota boi and KGB who just hung around) My facebook is private so don't try to find it. If you must contact me, send a message on youtube. If you want to get your ass handed to you on MW2 my psn is tehlogicboy. Well thats all for now. goodbye.

Posted by Fred the Penguin 8 years ago  |  last reply 8 years ago


the new shotgun on the block -EDIT-

-EDIT- Ok guys I sorry about not getting the pictures up but I do have an explanation. the picture shown was taken with my father's camera as I still cannot find the charging cable for mine. He "needs" his camera for work so I must wait indefinitely until I can "borrow" it to get some more pictures --------------------------------------------------------------------------------------------------------------------------------- Modern Warfare 2 confiscated? No computer or tv until 4 o'clock? what am I supposed to do? Well here's the result of about 3 hours of boredom. Its a single shot shotgun that fires shells, however these shells are a red rod long and hold 3 white rods, plus reloading takes less than 10 seconds with a bit of practice. Range isn't too impressive, roughly 5 metres for 3 white rods and up to about 10 for a yellow.  More pictures will be up once I have finished exams on Friday this week,  45º handles FTL!!!

Posted by Fred the Penguin 8 years ago  |  last reply 7 years ago


Cool Tool - Basic Stamp Logic Analyzer

A month or so ago Parallax had their basic stamp logic analyzer on sale for $30, so I picked it up. Its a slick little tool . It is handy to use when testing your wiring and software. If you have a BS2 and see it on sale again over at Parallax check it out. The only downside is the software is windows only, so mac geeks like myself will have to use a VM. -Joe

Posted by joe 10 years ago  |  last reply 10 years ago


Search Bug.

Whenever I use the search tool in the search bar, my avatar in the corner changes to what I think is Logic Boy's avatar. Below is a screenshot. Anyone know what's happening?

Posted by The Jamalam 8 years ago  |  last reply 8 years ago


Attention! All other Logic Bows are now obsolete

Well I took apart my sniper because it had really bad range, and I though well what now. I built a Logic Bow The new version is shorter, cleaner and much better looking. It also is a heck of alot more powerful. The new design incorperates a pin guide that prevents the pin from lifting when fired (this was my biggest gripe with the original) It is better than any other version in every way. I will be posting this as a seperate instructable as basicly the entire gun has been redesigned. Unfortunately I cannot post any pictures until I have found the charging cable for my camera ='(. thats all for now.

Posted by Fred the Penguin 8 years ago  |  last reply 8 years ago


90 degree turn of a line follower robot

I want a line follower to follow this track and when it comes back to the start point i want it to take the path of the starting point again not the forward path and so on . ONLY BY USING LOGIC GATES ( no micro-controller, Arduino..etc )

Asked by superdz 3 years ago  |  last reply 3 years ago


FSSG

Here is the video for my new gun, I cannot add it to the slideshow (obviously) so here it is

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago


Touch pad using tester logic? Answered

Hi everyone,                  I was planning to make a doorbell of which's switch is a touch pad.I tried understanding the logic behind the touch screens used in i phones and such otherd but they seem a bit complicated.Another solution I got was a circuit which has two free wires and when a person touches the two wires(creating contact),the load gets power.This is based on transistor switching.But I don't want to adopt this design since........ I don't know for some reason.Then I remembered those classy electrical testers(seen in the picture).They have a neon bulb in them which glows when they get a voltage of certain range from one end and our body is used as ground when the other end is touched.So if I use this mechanism I just have to use the setting to power the load when a metal plate connected to one end is touched by a 'user'and a voltage is given through the other end.I know these things usually have a neon bulb as they handle AC voltage.Finally here's what I actually need to know- Is it possible to build such a circuit where a 12 VDC is supplied to one end and the load is given power when the other end meets ground(here the person touching the pad).Maybe this might be a total jabberwocky but anyway contribute your valuable suggestions.If anyone has seen such circuits elsewhere, a schematic could be really helpful.Thank you in advance. 

Asked by Adarsh_tronix 5 years ago  |  last reply 5 years ago


Transistor NAND Gate does not completely work.?

I have been trying out some logic gates using transistors and I am confused already. I have built a NAND gate using 3 2n3904 BJT's. The resistor values are aprox the values in the schematic. The Diodes are 1N4003. Vcc is 5v (~4.9v) The schematic can be found here https://www.instructables.com/id/Digital-Logic-Gates-Just-Using-Transistors/ I have everything hooked up like the schematic shows. The issue I am having is that it is not working as I would expect a nand gate to work. The truth table shows that if A and B are both Low then C is High.  If A is High and B is Low then C is High. If A and B are both High then C is Low Here is what really happens.  A Low: B Low: C High A Low: B High : C High A High: B Low : C Low (but still ON just very very dim) <=Shouldn't this still be a High state? A High: B High: C Low Does any one have any ideas as to why it is behaving like this. I have rebuilt this circuit about a dozen times now making sure I have things correct. I am stumped.

Asked by atrumblood 6 years ago  |  last reply 6 years ago


Knex wars

Well here it is a shiny new forum were you can talk about knex wars. Me and my friends generally have one each month so you can expect a recap of each one. Also I would love to hear what you guys get up to.

Posted by Fred the Penguin 9 years ago  |  last reply 9 years ago