Relays? Answered

What is a relay and how to use it?

Question by Ahtasham Ahmad Mohtashim   |  last reply


Looking for relay

I have been looking for a relay that will switch with .3 vdc.  The other side is just a 9vdc source but the trigger has to be .3vdc or lower. thanks

Topic by zuben   |  last reply


Arduino Relay?

I'm working on a UPS of sorts for an arduino project of mine. Basically if the pwoer goes out I want the arduino to switch to a 9v battery backup. I was wondering what sort of relay I should use and if a transformer would be needed. Ideally I'd like to use a simple power supply with a transformer built in and then have that feed into the relay, but I'm not sure if the 7-12v from a normal arduino power supply would then be enough to switch the relay (normally closed).

Question by DELETED_maboy   |  last reply


Relay Schematic

I have a 1 volt signal that I need to latch open a 12 volt circuit for about a minute. Does anyone have a schematic?  

Topic by Divet   |  last reply


Relay timer?

I asked this question in forums before i knew about this so sorry for the copy. i hope someone can answer this here. i am currently engaged in a project where i need to create a count down timer relay controller. i was thinking of using a digital alarm clock as part of my goal is to have the display visually counting down, but i don't know of any that have a count down feature. i want the timer to power a relay to turn a string of IR emitters on for several seconds. i have a digital kitchen timer that counts down, but im not sure if it will work. i would like to use the power to the buzzer to activate the relay but there is no stable current there, it only Emits several beeps in quick succession(when i meter it, it comes out to about . volts). this is why the alarm clock would be better. i was hoping to use an electromechanical relay but i don't think it will work. does anyone know of another relay that will trigger with this kind of input?

Question by gedion4000   |  last reply


Relay Timer

I am currently engaged in a project where i need to create a count down timer relay controller. i was thinking of using a digital alarm clock as part of my goal is to have the display visually counting down, but i don't know of any that have a count down feature. i want the timer to power a relay to turn a string of IR emitters on for several seconds. i have a digital kitchen timer that counts down, but im not sure if it will work. i would like to use the power to the buzzer to activate the relay but there is no stable current there, it only Emits several beeps in quick succession(when i meter it, it comes out to about . volts). this is why the alarm clock would be better. i was hoping to use an electromechanical relay but i don't think it will work. does anyone know of another relay that will trigger with this kind of input?

Topic by gedion4000   |  last reply


Timed Relay?

I want to make an outlet that turns on with a button and automaticly turns off after about 30 minutes or so. somethimes i forget to turn my soldering iron and hot glue gun off and its not good for either of them to keep them on for long periods of times( or several weeks..) can anyone help?

Question by ingkiller   |  last reply


Choosing a relay?

I was about to make a project, I was all set then I realized that I hadn't chosen a relay yet. (Circuit http://2.bp.blogspot.com/-IdzxyPF4WYE/UfBCWb0deoI/AAAAAAAADZs/1-eYB2ufQCA/s1600/Clap+Switch.jpg) As I didn't know anything about relays or AC voltage I started studying. At the end I came to this. As I will be controlling lamps with either incandescent bulbs or led bulbs and phone chargers a 5v, 220v 1a relay will be enough, since Bulb 0.27 A, LED 100 MiliAmps and Phone Charger a few watts. So the question is that are my calculations right and what else should I know about relays e.g operating voltage resistance and other stuff. Oh and is there a 0.5a relay and if there is will that be enough? Thanks in advance. -Prickly Potato 

Question by SA-DIY   |  last reply


Variable Relay?

 Hi Instructables!, I'm working on a project to control a robot from the web but before I build it I want to find a way to control 24v motors from a laptop parallel port using relays and another power source. My problem is controlling them variably like from a joystick without going either on or off. I do happen to have an arduino microcontroller I could use but I was hoping not to simply for ease and cost reasons. Thanks for your help :)

Question by cornboy3   |  last reply


Undercurrent relay

Hi, Does anyone know how to make one of these Cheers

Topic by eddcole   |  last reply


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

Topic by bart245   |  last reply


Voltage Relays

Hello, I'm new to this board, and well, making things in general, and am particularly stumped about voltage relays. I know in theory how they work, a small voltage triggers a circuit to close and let a larger voltage through, but practically have no idea what the terminology used in the data sheets mean. What I'm looking for is to have 120VAC be triggered by a 5VDC. The 120VAC would only be on as long as there was 5VDC triggering it. Can anyone out there tell me what I should be looking for, in particular, what the voltage that causes the circuit to close is called? Thanks. --D.K.

Topic by Knip.   |  last reply


Bunch of Relay Questions? Answered

Hey Guys This will be my first relay project and I have a few questions regarding how to wire up a relay and such.....well there is not much to say, all the questions are in the diagram. So....yeah.

Question by SA-DIY   |  last reply


Relay with small in size

I have a relay with an Outline Dimensions:(15.5x10.5x11.8)mm 5V,3A--> Switching voltage 230VACDatasheet is given above..could you suggest the similar capacity with small in size (not a solid state relay) relay ??i was search website like MOUSER,LCSC .didn't find any suitable one.

Topic by shavanwe0   |  last reply


Questions about relays

I am building a robot with a specific purpose and I have hit a snag. My remote controls on the receiver end are 4.5v and the motors I want to run are 12v all of it is DC. The relays I have don't pull in a 4.5v so I need another way to doing this. I either need another way of pulling in the relays; I need relays that pull in at 4.5, or some other intelligent solution that I cannot think of. Please help!

Topic by kendallickes   |  last reply


computer controlled relay

I want to build a SIMPLE computer controlled relay. Not where u have the relay that is on when the computer is on, the kind where u have a program that has little buttons that u click to activate a relay. Please help me!!!!!

Topic by sci4me   |  last reply


Transistor relay with NO and NC?

Does anyone know how to make a solid state relay with a NO contact and a NC?Does anyone have a schematic?Thanks.

Topic by thermoelectric   |  last reply


working with relays and arduino

I am doing a project in which i need to switch 3 phase induction motor( star connected ) using relays one for each phase and 3 phase voltage in our country is 415v( phase to phase). so my question is can I use relay of  rating 250 volts 5 amps one across each phase and 1 phase supply in our country is 230v .

Question by nanu146   |  last reply


solid state relays

I have four, 5A, 280V solid state relays. They are activated by 3-8V. I need to tie them together so that I end up with a total of 20A. Do I tie them in series, or parallel? Also, do I tie the inputs in series or parallel so that there is one input? Thanks.

Topic by gimmelotsarobots   |  last reply


Switch/Relay Question? Answered

I've been working alot with capacitors recently at a voltage of 330v or so. I've been using this cap bank to discharge into whatever I feel like. Wires (to watch them pop), cds (to "erase" them), etc. Anyway, one problem I've been having is the switches. I flip the switch, it discharges the capacitors and it should work fine. The only problem is the switches are only worth one shot. And I'm using the biggest I can find. (Rated for 15 Amps). I realize that the capacitors are discharging instantly, and the amperage is probably higher then what its rated for, but I expected to get more then one shot out of it. Any suggestions besides a bigger switch? (I've considered using a series of relays for each capacitor, but that gets expensive.) Thanks!

Question by transistorguy   |  last reply


Why these relay issues?

In my PCB ,AC voltage is passes under the relays(R).. relays too become heat up.

Topic by sforsajith   |  last reply


Shift Register and Relays? Answered

Using a 74hc595 shift register to a ULN2003 darlington array to control 7 relays, all controlled by an MSP430, connected via RJ11.  The relays are controlling LED Christmas light strings on and off.  Everything seems to be functioning so far but the problem is that relays that aren't being told to turn on sometimes are turning on.  The shift register is connceted with Qa to the master reset of the register so I can clear is quickly, but so far I have been just leaving it high.the other 7 outputs (Qb - Qh) connected to the base pins of the ULN2003 (B1 - B7).  The outputs of the ULN2003 connected to the relay coils, COM connected to 5v, emitter connected to ground.  I have tried pull down resistors on the base pins, I have tried tweaking the code which I tried to set up to just bit bang the shift register, make it as simple as possible just to test it and a sample is provided below for one iteration.  I have it looping through several of these to turn a single channel on each time to check to make sure all the channels work.  It however sometime make a channel just flicker, not turn on at all, or turns several channels on at the same time.  I am curious as to whether this is a hardware problem (pullup/down resistors, filtering caps, more clamping diodes then what is built into the ULN2003, whatever) or whether I am just an incompetent programmer.  I am fairly certain the problem lies somewhere between the driver seat and the steering wheel though.  One thought I had but do not want to try right away is it possible the shift register is bad?  Overheated from soldering?  I try to solder one pin on chips, then a pin on another component, then a pin on the opposite side of the chip, etc to keep chips cool when soldering them, but are the 74hc595 very heat sensitive maybe?  Would appreciate a fast answer, looking to build 5 more of these so I can control all my Christmas lights. This was supposed to be a cheap and dirty project so I didn't get into Triacs and dimming, I just want to turn lights on and off as I see fit.   i = 30000;   P1OUT = 0x00;        //Channel 7 (unused)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT = 0x01;        //Channel 6 (Green Wreath)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT = 0x00;        //Channel 5 (Red Icicle)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT = 0x00;        //Channel 4 (White North)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT = 0x00;        //Channel 3 (White South)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT = 0x00;        //Channel 2 (Blue North)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT = 0x00;        //Channel 1 (Blue South)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT = 0x01;        //Channel 0 (Clear All/Active Low)   P1OUT |= 0x02;       //Clock in   P1OUT &=~ 0x02;   //Clock low   P1OUT |= 0x04;       //Latch outputs   P1OUT &=~ 0x04;   //Latch low   while(i > 0)   {         i--;   }

Question by Electric Spectre1   |  last reply


need relay help

Hi all, me and a friend are working on project and i'm trying to figure out how to make a solid state relay out of a night-light. the problem is that the light turns on when the photo sensor fails to sense light. i would much rather the light would activate when the sensor detects light. any ideas?

Topic by synthetic_iron_oxide   |  last reply


proximity chip relay

Not sure if in correct forum but here goes... I'm wondering if someone could design a simple and inexpensive way to use a chip to trip a relay with proximity. An idea I have for vehicle anti theft. possibly to bypass need for ignition barrel etc. but to allow the car not to be started without the presence of a close by chip. any ideas?

Topic by astrosurfer   |  last reply


LED Flasher Relay

Can anyone help me build a LED flasher replay capable of running approximately 100 LED's. I would like it to alternately flash and have a strobe like effect, similar to what most emergency vehicles have!!! Thanks Dave

Topic by Jeepcop274   |  last reply


Use an AC relay with DC?

Alright so I want to make something to magnetize screwdrivers with a pulse, basically taking the 400 volts dc from a PSU's capacitors. I have a few relays from some UPSes, however they are all rated for AC except one which also does DC, but significantly less than the AC rating. The first relay I have s an OEG 0Z-SS-112L It seems to be triggered by 12v DC, and can take 120vac at 20 amps, 240vac at 16 amps, but on the other side of the relay there is the circuit marking for a switch, with 16a/240v~ and 16a/30v~ on it. My next relay is an OEG ORWH-SS-112D1F It's marked for 15a 125vac and 10a 277vac My next relay is an omron G2r010E, and is markes for 12 amps, either 240vac or 16vdc My last relay option is a schrack RP 710024, apparently switching with 24vdc and rated for 16a, 250vac So, can I use any of these with high voltage dc? What is the difference between a DC and AC relay?

Question by XOIIO   |  last reply


4 channel 12v relay board

I'm looking for a 4 - channel 12v relay board that can be controlled by a pc either by usb or Bluetooth. Each channel needs to support 5A minimum and control software should come with the board. Anyone know of a decent one?

Question by srowland2   |  last reply


how do i conect a 6v relay ? Answered

(the 5 connections relay)

Question by juankppo   |  last reply


220V 1000times a second transistor/relay?

I need a transistor/relay that can operate under 220V and can open and close itself a 1000 times a second. Does such a thing exist?

Question by yonch   |  last reply


Did I choose the right relay? Answered

I am building a circuit in which a photoresistor triggers a relay which then powers a motor. The motor runs on a max of .75 amps and uses 4.5 VDC, while the photoresistor side must use a max of a few milliamps and can use anywhere from 1.5-6 VDC. This is the relay I am thinking of: http://search.digikey.com/us/en/products/TXS2-L-12V/255-1898-ND/650137 . I am pretty sure it's the right one, but I wanted to make sure. Is this the right relay for my purposes, and if not, what's wrong with it?

Question by seraine   |  last reply


Is there a relay that uses a 110v trigger for a 12v output? Answered

I know that this is probably the most backwards way to do things (and yes, I know, probably extremely stupid [but I'm also new to relays..]) , but I am in the process of trying to make a heated platform for my RepRap (I have gen 6, thus the reason for this). I have a PID controller, and I have the board running off an ATX power supply. So, what I would like to know if there is a relay that can use the 110v the PID controller to turn on/off the power from the ATX to the heat bed.  Thanks in advance! 

Question by DoctorWoo   |  last reply


I need a relay to run from an ATtiny85 chip.?

I need a relay that can be switched from an ATtiny85 chip output pin, and can be used at 120V AC and 15A. Otherwise I will need to use a transistor, but hopefully I won't. What about the ATMEGA328 instead of the ATtiny85? Thanks guys and gals.

Question by Geniusdude   |  last reply



Does anybody know about electrical relays, please? Bi-Switching Circuit Needed to Control 2 x 1000w Kilns On and Off.

I have a workshop which has 2 x 1000w kilns. To fire my pottery etc, I need to put a kiln on for about 12 hours. No ordinary cheapo timer can handle the wattage load and so I am thinking of using a heavy-duty relay. Are you good with relays? If so, I would value your help, please. What I want to do is plug my timer into the mains socket, have the relay connected to the timer so that it knows when to switch on and off, and then I need two outlets (one for each kiln) so that when one is switched on, the other is off, and so on. I have thought of a 30A, 240v relay which is SPDT. I have deliberately over-specified the relay because I want it to be safe and to last, as well as use the thing for other applications where there may be a large inductive load (as opposed to resistive load). I can provide a link to the relay, but I'm not sure if this allowed. Many thanks. Kevin

Question by kevinhannan   |  last reply


Use 5sec pulse to generate only .5sec pulse ?

Hi, i use an internal relay of a phone system to open a garage door and the time of that pulse is 5sec and is the minimal time, but i need make a .5sec pulse to close, how can i use the 5sec pulse to generate another .5sec for close the door or just a momentary pulse ? Thanx !

Question by mike_k11   |  last reply


Switch a relay with a 555 timer?

I have a clap activated relay which I want to use to switch on my computer but when you leave the switch on my PC in the "on" position it just keeps rebooting. Would it be possible to use the relay to activate a 555 timer circuit or similar to the switch off the relay after 2 or 3 seconds?

Question by cheesemarathon   |  last reply


Reed relay to reed switch Answered

Can someone help me. I have a reed relay and want to use it as a reed switch. Can someone tell me hyow to hook it up so it acts as a reed switch?

Question by Adum24   |  last reply


Build a 3v Relay Module

Would love a 3v relay module that can be drive by PIRs that output 3v signal.  Thought I finally found what I needed on Ebay, but discovered this is a bogus product that actually needs 5v to be driven.  http://www.ebay.com/itm/5PCS-3V-3-3V-Relay-High-Level-Driver-Module-optocouple-Relay-Module-for-Arduino-/331413255692?hash=item4d29c4f60c:g:6koAAOSwfcVUDuEJ Buyer Beware. Advertised relay PCB as 3v relay. While the relay on the board may trigger independently with only 3 volts, the circuitry of the board demands a higher voltage to trigger the relay. Relay PCB has a EL817 opto-coupler for the input signal, it requires a 5V drive voltage on the Input in order to drive the onboard transistor which controls the relay coil current. With only a 3v drive, there is insufficient current to drive the opto and transistor. The module that the relay is mounted to is falsely advertised as 3.0V because the components on the board need more than 3 volts. In order to drive this relay with a 3v signal device, voltage level shifting needs to take place between 3v device and relay PCB.

Topic by DiyWaterDog   |  last reply


Arduino Uno Relay circuit

I am currently involved in a project that requires me to run a fan heater through coding in an arduino. I have decided to use a relay to act as a switch, to maintain the time period of heater running. I am using a DOAT 5V 20mA relay. I was wondering if anyone could help me with the circuit needed using a n-p-n transistor to power it while maintaining switch function. I know a circuit similar to the one below is needed, but im not sure about the capacitor and resistance values needed for a 5v, 20mA relay.

Topic by RoshanC1   |  last reply


Need help finding a relay

My school's building a biodiesel-hybrid car. Is there something like a normally closed relay that can be opened when the voltage goes over 165V. What should I be looking at?

Topic by agent   |  last reply


Should I use a relay?

Hello, I am trying to control a 9v DC pump with an arduino. I am thinking that I will need to attach a relay to the pump, and control the relay with a transistor from my arduino. Is this correct?

Question by KarateLover21   |  last reply


Replace DPDT switch with relay

Hi there, I'm currently using a DPDT switch to toggle between power sources (gray dots) I'd like to replace this with a relay, I've added blue dots to my drawing to show (how I think) that should look. Is this correct? My main concern is if I should take the coil resistance into account. What kind of relay would you recommend? Would any 12V 2A relay work? Kind regards, Niellles P.s. the 560 ohm resistor is on the other side of the led...

Question by Niellles   |  last reply


Quick question about relays?

Hey everyone, just a quick question here. I need a relay that will operate on 12V DC or less that can withstand 120V AC @ 2A (US sockets are 2A correct?). Would this work? Or am I oversimplifying everything?  http://www.radioshack.com/product/index.jsp?productId=12505678&retainProdsInSession;=1#tabsetBasic

Question by Geniusdude   |  last reply


Wireless control of a NC relay?

I'm sort of a newbie when it comes to this stuff. Originally I planned on just putting in a NC momentary switch. Now my idea has evolved, I would like a momentary switch to wirelessly control a relay. How would I go about setting up a wireless transmitter/reciever. Whether it be IR or something else.

Topic by Spamwich   |  last reply


usb Relay board wiring?

 Basically i've just purchased a relay board - i know the basics on how to wire it up but just had a question. Greatful if anyone in the know would answer for me: What are these terminals for - im guessing sensors or something? thanks

Question by DrWilson   |  last reply


off relay with delay on timer

Hello smart people! I need to pick your collective brain. The project that I am working on is on my car. I am replacing the front turn signals on my car with an LED strip. The led strip has three wires. One for ground, one for white LEDs, and one for the amber LEDs. If it is just directly connected to the current incandescent bulbs, the white comes on as a running light. When the turn signal comes on, the lights flash white, amber, white, amber..... (not what I want) What I want it to do is turn off the white while the amber flashes, then turn the white back on. I have a delay on relay, but that won't quite work for what I am trying to do. Isn't there a way to just throw a cap and resistor to keep the voltage on a relay to keep the white off till the amber is done flashing?

Question by DanielB93   |  last reply


LED relay switch... maybe?

First off thanks for looking and helping if you decide to. I have only been working with computer electronic in a DIY since for about a year. My question is, do I need a relay for what I am trying accomplish and if so what kind? What I am trying to accomplish is: I have two push buttons (momentary contract switches). And I want it so that when I press the first button (orange) the first LED turns on. And when I hit the second button (blue) the first LED turns off and the second one turns on. Kind of like a toggle but only with the LEDs. The buttons are also connected to a board that is connected to my computer via USB. Which is where the power is coming from for the LEDs. I can use another source if necessary. I drew a little picture to help describe what I am trying to describe.

Topic by Foreverhex   |  last reply


Using relays to control lighting?

I have one Banner QS18VN6LV Retro-Reflective light interruption sensor, and one Banner QS18VN6D sensor with NPN Relay outputs. How could use the set to say, power on lighting when one is interrupted and power them off when another is interrupted? What I want to do is use them in my home theater, to power on the room lighting, projector and audio equipment and lower the screen when the one at the top of the steps is interrupted, and power off the room lighting, and turn on my ambient LED lighting when the one at the bottom is interrupted. The only problem this may have, is that the retro one is always sensing something till interrupted, and the non-retro one is only sensing something when interrupted.

Question by macwhiz   |  last reply


remote actuator with momentry relay

Hi Firstly Im new to this and my electronic knowledge is very limited What im trying to do is make an actuator move up and down using a remote using a momantary action From what I understand I need and actuator (obviously), an ir remote and a power supply I have sourced a few parts (see below) just dont know how they will or if they can go together actuator: http://annbodesign.com/GENERAL-PURPOSE-ACTUATORS-FOR-AUTOMATED-PROJECTS ir remote: http://cgi.ebay.co.uk/12V-Remote-control-On-off-2-Channel-momentary-relay-/320627757256?pt=LH_DefaultDomain_3&hash;=item4aa6e750c8 So what i need to happen is that when i hold one of the buttons the actuator opens and when i hold the other button the actuator closes As i said im not sure how to or if these products will go together, so if not, please could you lead me to another website where i could get the products from, also not sure if i will need limit switches etc etc ps im in the uk, so a uk based site would be an advantage for me thanks pete

Topic by newbie308   |  last reply


solid state relay information Answered

Do I need to apply voltage to pin 5 for it to switch on chip Vishay VO14642AABTR? http://www.alldatasheet.com/datasheet-pdf/pdf/443188/VISHAY/VO14642AABTR.html

Question by jbaker22   |  last reply