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13 March 2010
Author: Giorgos Lazaridis
How Relays Work

Relay Types

There are so many different types of relays, that it would be literally impossible for me to add them in this article. Therefore, i will categorize the types of the relays in terms of:

  • 1. Turn ON/OFF operation
  • 2. Coil
  • 3. Contacts

  • Category 1. Turn ON/OFF operation
    Normal relays

    An octal 3PDT relay and it's base

    There are basically two types of relays in this category. The first type is the normal on/off relay. This relay changes state as long as the electromagnet is actuated, and goes back into relax state when the electromagnet is not actuated any more. This is the most common relay type and is used widely in automation.

    Toggle relays

    This type of relay operates just like a toggle flip flop. When the coil is once actuated, the relay will change state, and will remain in this state even if the coil in no more actuated. It will only change state again on the next pulse that will actuate the coil. This is very handy in modern house lighting. Having this relay instead of a switch, you can turn on and off the lights with one pushbutton. You press the pushbutton once and the lights are turned on. On the next pushbutton press, the lights are turned off.

    Latching relays

    A latching relay

    This type of relay operates exactly like the R-S flip flop. It has two different coils instead of one. When the first coil is actuated, the relay goes to the SET position and it remains there no matter if this coil is kept actuated. It will only change state (to RESET position) only if the other coil is actuated. This type of relay is widely used in applications where the state of the relay needs to be kept as is, even after a power failure or a restart.

    Protective relays

    I will distinguish this type of relays in two sub-types. The first sub-type is the current-leaking protective relay, and the other type is the overload protection relay.

    Protective relays - current-leaking

    A current leaking protection relay

    Almost everyone knows these relays. They does not actually have an electromagnetic coil. Instead, they remain armed all the time. Two electromagnets are placed one opposite the other. Between them, there is the armature. This armature is magnetized from both electromagnets. The first electromagnet is placed in series with the Phase, while the other is connected in series with the Neutral. If the current that flows through both electromagnets is equal, then the armature is kept in balance. But if the current that flows through the second electromagnet is less than the current that flows through the first electromagnet, then the armature is pulled to the first electromagnet that has greater magnetic force! And how can this happen? Easy, if somehow an amount of current flows to the ground of the installation...

    These relays can (and SHOULD) be found in every household electrical installation, right after the main switch. Look at the following illustration:

    The light bulb is turned on because the magnetic power from both coils is equal. Now look what happens if "somehow", the current on the neutral is less than the current on the phase. The magnetic power of the electromagnets is not equal, thus the relay will cut the power supply and our friend will be saved. For safety reasons, if this happens, the relay can only be restored mechanically, if someone pulls the lever of the relay up again:

    Protective relays - overload

    An overload protection relay

    Very common relays in motor applications, as well as in all electrical installations. These relays wave no electromagnetic coil to move the armature. Instead, they have a bimetallic strip that the current flows within. The material and the thickness of this strip is carefully selected, so that it will be heated (and thus bended) above a specified current value. When the bimetallic strip is bended, the relay will cut-off the power supply. For security reasons, the relay can only be restored mechanically by moving the lever by hand.

    This is the basic idea of the overload protection relay. If one line is overloaded, the bimetallic strip is overheated and thus it bends, breaking this way the contact

    It should also be mentioned that there is another kind of overload protection relays called "electromagnetic relay". This operates exactly the same as the overload protection relay, but has inside also another electromagnet. If this electromagnet is powered, then the relay will be forced to break connection, as if it was overheated. This functionality allow to check for faults and stop a motor to avoid any other problem, even if the motor itself is not overheated.

    Temperature relays

    A temperature relay, AKA thermostat

    These relays operates similarly to the overload protection relays above. The major difference is that the bi-metallic strip is not heated by the current that flows within the strip, but from an external factor. This factor could be the ambient air, water temperature, another fluid refrigerator temperature etc. You may know these relays with another name... thermostats, used extensively in heating applications.

    Another difference from the protection relays is that the temperature relays usually do not need an external mechanical movement to restore it's state. The process is done automatically according to the temperature of the bimetallic strip.

    Reed relays

    You could imagine a reed relay like a relay without an electromagnet. The reed relay's armature is actuated from any other external magnetic field. The reed relays can be found in door monitoring systems. A permanent magnet is attached to a door, while the reed relay is right above the magnet. If the door opens, the state of the reed relay is changed. Another common application for reed relays is on the speed meters of the bicycles. A permanent magnet is attached to the wheel of the bicycle, while the reed relay is fixed on the "fork" of the bike. Every time the wheel rotates and the magnet passes in front of the reed relay, it sends a pulse to a microcontroller.

    Other relays

    There are many other types of relays like the timers and the function relays, but they use some kind of circuitry to perform different actions. I will not go into these categories, as this article is only interested to the kind of relays that uses no other circuitry, only mechanical variations.

    Category 2. Coil actuation

    Another type of relay categorization is the coil. In this category i separate the relays according to the way that their coil is powered to actuate the armature. So we have:

    AC/DC relays
    ... straightforward... The coil can operate with either AC or DC voltage.

    Neutral relays
    These relays have the most common coil. The armature is actuated when current goes through the coil, regardless the polarity.

    Biased Relays

    A permanent magnet is attached to the armature

    This is a variation of the neutral relays. These kind of relays have exactly the same coil as the neutral relays, but they carry a permanent magnet on the armature. The polarization of the magnetic field of the coil depends on the polarity of the supply. Therefore, the armature is actuated only if the polarity of the coils' magnetic field is opposite to the polarity of the permanent magnet's magnetic field. This way, the relay is actuated only if the coil is correctly biased.

    Polarized relays

    This kind of relays operates exactly the same as the biased relays. The only difference is that these relays does not have the permanent magnet, instead they have a diode in series to the coil. If the diode is correctly biased, the coil will have power and the armature will be actuated. The difference that makes these two relay types different is that the biased relays will allow the current to flow through it's coil, even it the relay is reverse-biased! Very important if someone wants to connect the coils of two or more relays in series.

    Solid State Relays (SSR)

    This is the modern type of relays. These relays does not have a coil, nor any other moving part, that's why they are called Solid State. They are used for fast switching (up to several hundreds of Hz) and for controlling loads in explosive or harsh environments. They have significantly more lifetime than the conventional relays, as their contacts will not corrode due to humidity, dust or other causes. Actually, they do not have contacts! Instead, a FET or a TRIAC is used to simulate the contacts. The major disadvantage is the price...

    Category 3. The contacts
    The third and last category is the contacts of the relays. There are 3 major characteristics that distinguishes the relays:
  • 1. The max voltage: This characteristic is determined by the gap that exists between the contacts, as well as the alloy that the the contact is made of. The higher the gap the higher the voltage that a relay can cut-off.
  • 2. The max current: This characteristic is determined by the thickness of the contacts, as well as the alloy that the the contact is made of. The thicker the contacts the higher the current that a relay can handle.
  • 3. The switching frequency: This characteristic is determined by the mechanical construction of the relay. The lighter the construction, the faster the switching.
  • 4. The number of contacts:...Just the number of contacts...
  • As far as the contact number is concerned, the relays (like the switches) comes with some kind of coding. The general code form is this:


    The 'P' stands for "POLES". The 'x' is the number of "POLES" that a relay has. Thus, if a relay has 1 contact pair (POLE), the code would be SP as for Single Pole. For two contact pairs, it would be DP as for Double Pole. Above 2 contact pairs, the x gets the number of poles, eg for 3 poles it would be 3P etc etc.

    The 'T' stands for "THROW" and 'y' is the number of "THROWS". 'y' can be Single or Double. Single Throw (ST) means that there is only one NO or NC contact. Double Throw (DT) means that the relay has pairs of NO/NC contact.



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  • At 10 January 2016, 14:51:46 user deva wrote:   [reply @ deva]
    • Great Job , every thing is clear thank you so much

  • At 10 March 2015, 5:20:38 user Amin shaikh wrote:   [reply @ Amin shaikh]
    • thank you sir....
      you can give proper working principle of reiay in simple language.

  • At 4 January 2015, 9:18:31 user Giorgos Lazaridis wrote:   [reply @ Giorgos Lazaridis]
    • Well here is the deal. Long long time ago, the switches were like "knife" switches (check this page http://upload.wikimedia.org/wikipedia/commons/4/4b/Open_knife_switch.jpg)
      See the similarity of a relay contact? The blade connects to the common, the other end that the blade goes in is the NO contact. So, it was common place to connect the live to the NO contact as safety measures, so that when the switch was off (open) the blade that was exposed would have no power.
      BUT, this is not common use an more. Here is the other deal. If you want the relay to switch power between two loads, then the the live should go to common. Say for example that you want to power a traffic light for pedestrians, it can either be GREEN or RED, never both. So you connect the common to live power, the NC to RED and the NO to GREEN. Arm and disarm the relay to turn each of the lights ON or OFF...

      So, it has to do with the operation that you want to perform.

  • At 28 December 2014, 11:15:29 user Pammi wrote:   [reply @ Pammi]
    • Thanks a lot Giorgos..

      I am new to working with Relays. Therefore, I have just one more question :-

      In various other tutorials on Relays, I saw that LIVE wire was always connected to the 'Common' port of relay, and neutral to NO/NC (via Bulb/Microwave).

      Is there any specific reason for that ?

      I personally think that even if we connect the LIVE wire to NO/NC, and COM to neutral wire, it does not matter. It is one and the same thing.

      But still wanted to have your view on that. Anything related to safety or something ?

  • At 28 December 2014, 10:54:05 user Giorgos Lazaridis wrote:   [reply @ Giorgos Lazaridis]
    • @Pammi that would work the same, no problem.

  • At 28 December 2014, 10:20:19 user Pammi wrote:   [reply @ Pammi]
    • This is so clear. Thanks !

      I have a small Doubt: Why is the microwave (or any other AC component) is connected to power via NO/NC? Can we not the AC component to power via Common port of the relay ? Will there be any issue?

  • At 7 November 2014, 17:33:08 user mahdi wrote:   [reply @ mahdi]
    • its the best explain about work relay.TANKS

  • At 18 October 2014, 11:01:45 user sri wrote:   [reply @ sri]
    • will u please tell me brief about armature.

  • At 18 October 2014, 10:59:11 user sri wrote:   [reply @ sri]
    • Thank you very much. It is good and the practical which u have shown is excellent and very understandable to me.

  • At 7 October 2014, 13:57:26 user nivedha wrote:   [reply @ nivedha]
    • awesome
      i understood clearly
      thanks a lot

  • At 18 September 2014, 13:50:07 user karim wrote:   [reply @ karim]
    • Excellent sir

  • At 29 July 2014, 16:19:53 user ganesh wrote:   [reply @ ganesh]
    • thank you so much sir

  • At 16 July 2014, 15:51:06 user deb sankar mukhopadhyay wrote:   [reply @ deb sankar mukhopadhyay]
    • your explanation and animation is just awesome, keep the good work, God bless you.

  • At 15 July 2014, 9:36:00 user Tony wrote:   [reply @ Tony]
    • good work..can yoy tell methe industrail realay connection and how its working

  • At 23 May 2014, 19:27:21 user niki wrote:   [reply @ niki]
    • AWESOME tutorial. Basic concepts of relay is covered very well.
      5 starts to the author.

  • At 10 May 2014, 12:15:23 user meghan wrote:   [reply @ meghan]
    • Awesome to Undestanding..............

  • At 8 May 2014, 9:13:59 user Mohammed Wajeed wrote:   [reply @ Mohammed Wajeed]
    • hurrayyy !!!! finally found the way how relay actually works.. thanks for your good explanation and hard work :)

  • At 7 May 2014, 10:14:54 user RAJESH G wrote:   [reply @ RAJESH G]
    • first of all .i thank uuuuuu..for this web page....it give more knowledge on basics ...thank u

  • At 13 April 2014, 16:33:02 user jeff wrote:   [reply @ jeff]
    • i am a student and i found this very informative and understandable. thank you for this as i am sure i will reference it often.

  • At 2 April 2014, 8:37:04 user Ram Krishna Sharma wrote:   [reply @ Ram Krishna Sharma]
    • Very good material conceptually as well as analytically. It will help students in projects as well as in ordinary applications of switching.

  • At 13 March 2014, 18:31:44 user Michael G wrote:   [reply @ Michael G]
    • Thank you for this post. Of EVERYTHING on the internet about relays, this post finally made me understand.

      Thank you. Thank you. Thank you.

  • At 5 March 2014, 11:22:50 user sikandar wrote:   [reply @ sikandar]
    • awesome !!!!!!!!!

  • At 3 March 2014, 3:46:31 user MOHD IMRAN QURESHI wrote:   [reply @ MOHD IMRAN QURESHI]

  • At 23 February 2014, 15:10:28 user godfrey wrote:   [reply @ godfrey]
    • Good and technical explanation
      But where does the neautal go.thx

  • At 18 February 2014, 15:39:54 user kunal wrote:   [reply @ kunal]
    • so nicely explained...

  • At 17 February 2014, 22:26:59 user SURAJ wrote:   [reply @ SURAJ]
    • Awesome to Undestanding..............

  • At 24 January 2014, 14:53:17 user ravi wrote:   [reply @ ravi]
    • nice and clear and got understood thanks a lot and keep giving information like this which helps us to improve our knowledge thanks............

  • At 3 January 2014, 9:54:45 user sahabh wrote:   [reply @ sahabh]
    • Jabardast...!!! THANX..!I Like it.

  • At 15 December 2013, 6:05:06 user Ashesh Kharidia wrote:   [reply @ Ashesh Kharidia]
    • Understands Basics very easily. Very Nice

  • At 26 November 2013, 4:17:32 user Gaurav wrote:   [reply @ Gaurav]
    • Nice and Clear. Animation is self explanatory. Thanks.

  • At 24 November 2013, 18:27:24 user Rayar.B wrote:   [reply @ Rayar.B]
    • Very nice explanation

  • At 9 November 2013, 11:32:21 user naresh wrote:   [reply @ naresh]
    • nice teaching...... easy to understand

  • At 26 October 2013, 17:32:41 user shradha g wrote:   [reply @ shradha g]
    • wooww.... nice..easy to understand . :)

  • At 7 October 2013, 3:23:11 user aniket wrote:   [reply @ aniket]
    • very nicely written & it helps me to understand relay very nicely....

  • At 18 September 2013, 11:19:41 user Jacky Woo wrote:   [reply @ Jacky Woo]
    • Hi, I have a usb relay current - Up to 16Amp @24vdc or 250vac, I wanted make it work like a light switch to turn on a light on my front door! How would i wire it? Thank you in advance!

  • At 16 September 2013, 11:21:58 user manikappa wrote:   [reply @ manikappa]
    • this nice experiment......

  • At 9 September 2013, 14:58:18 user chandan shee wrote:   [reply @ chandan shee]
    • very nice explain

  • At 29 August 2013, 6:17:34 user saravanan wrote:   [reply @ saravanan]
    • explaniation is very good.. keep going on... thanks a lot...from hereafter i can do the mini projects in my home... this website very useful for all... thanks alottt....

  • At 24 August 2013, 2:50:56 user FatnessFirst wrote:   [reply @ FatnessFirst]
    • I just want to say. THANK YOU. I've been researching about relays for 5 hours straight only to be left confused. You pretty much showed it in such an easy way and EVEN STATED that their are different kinds and purposes...no wonder i'm god damn confused the whole time

  • At 20 August 2013, 11:29:43 user sanam pudasaini wrote:   [reply @ sanam pudasaini]
    • very good post... :) i expect more such post in coming days...

  • At 3 August 2013, 6:59:04 user Jableen wrote:   [reply @ Jableen]
    • a lot helpful

  • At 26 July 2013, 15:39:56 user birendra wrote:   [reply @ birendra]
    • very useful information ! thanks a lot, you really cleared my doubts regading relay opertaion. now i can do my home automation project without any fear of damaging my arduino.,

  • At 23 July 2013, 19:25:39 user Jayesh wrote:   [reply @ Jayesh]
    • Grate....
      Well teaching trick....

  • At 20 July 2013, 5:32:09 user ananth wrote:   [reply @ ananth]
    • nice explanation

  • At 19 July 2013, 7:27:22 user TALHA wrote:   [reply @ TALHA]

  • At 11 July 2013, 13:06:14 user owen wrote:   [reply @ owen]
    • thanks i found it very virtal for i was confused on how i can make an automatic gate closer. If u do mind please asist me wth more illumination to this e-mail okamphata@hotmail.com thank u pipo

  • At 23 June 2013, 16:02:02 user Lance wrote:   [reply @ Lance]
    • Nice post. Short and sweet.

  • At 23 June 2013, 10:05:34 user Nelly wrote:   [reply @ Nelly]
    • Hi I have too signals to be brought back using relay? or relays? one is 24vdc for a plc signal and the other is volt free for a telemetry alarm how can this be done?

  • At 20 June 2013, 4:43:10 user online education wrote:   [reply @ online education]
    • it is really very good post..

  • At 20 June 2013, 4:11:08 user Gramzrah wrote:   [reply @ Gramzrah]
    • Thanks I Salute you

  • At 6 June 2013, 5:59:15 user zaeem wrote:   [reply @ zaeem]
    • nice one

  • At 21 May 2013, 15:22:39 user salik wrote:   [reply @ salik]
    • thanks brother it was very helpful for me. Nice animations.

  • At 14 May 2013, 9:52:19 user Best wrote:   [reply @ Best]
    • This is very helpful! Thanks a lot for your efforts!

  • At 10 May 2013, 11:46:44 user amol wrote:   [reply @ amol]
    • very simple to understand and impressive.

  • At 20 April 2013, 2:26:14 user sudeep wrote:   [reply @ sudeep]
    • very nice explanation....good method to understand...use of animation is very helpful in understanding the concept...thanx alott:-):-)

  • At 15 April 2013, 21:10:17 user Snehal wrote:   [reply @ Snehal]
    • Great explanation ! I finally have understood how a relay works ! I hope u keep the website updated with more explanations !

  • At 11 April 2013, 10:59:49 user Harry wrote:   [reply @ Harry]
    • thank you for giving this information,it is easy to learn and nice explanation....

  • At 10 April 2013, 17:49:12 user Abhijeet wrote:   [reply @ Abhijeet]
    • good one! very helpful, thanks...

  • At 8 April 2013, 10:04:57 user kanyakumari wrote:   [reply @ kanyakumari]
    • very good explanation with showing pictures thanks a lot

  • At 5 April 2013, 9:22:27 user Neelam wrote:   [reply @ Neelam]
    • thanks for giving clear idea about relay.

  • At 29 March 2013, 20:19:17 user Giorgos Lazaridis wrote:   [reply @ Giorgos Lazaridis]
    • @ashmit maybe you want to control high load with small pushbutton or low voltage

  • At 29 March 2013, 11:31:57 user ashmit wrote:   [reply @ ashmit]
    • why do we have to use the electromagnet to put the switch on and y cant we just make the contact with a simple switch.

  • At 20 March 2013, 15:32:40 user manoj raut wrote:   [reply @ manoj raut]
    • That is very good method of understanding of relay opertion .
      But ,can you explain how can we are use relay for fan control

  • At 19 March 2013, 8:47:06 user saheer wrote:   [reply @ saheer]
    • Very helpful explanation thank u so much.......

  • At 18 March 2013, 13:01:41 user Mnagesh wrote:   [reply @ Mnagesh]
    • Can you please explain me what is meant by the "Potential free relays".
      As i want to integrate my device with the SCADA system they asked me to provide signal to SCADA device for 5 sec( means i want to complete there circuit using a potential relay) with the help of potential relays only.
      Or can i use any kind of relay to complete there circuit.

  • At 18 March 2013, 9:42:24 user Anusha wrote:   [reply @ Anusha]
    • Thanks a lot :)

  • At 11 March 2013, 17:47:43 user kiran kumar wrote:   [reply @ kiran kumar]
    • An easy way to analyse

  • At 10 March 2013, 18:20:53 user kiran wrote:   [reply @ kiran]
    • really great!!!! this is so helpful....

  • At 7 March 2013, 19:56:21 user kimani morgan wrote:   [reply @ kimani morgan]
    • sent me more ok.!!!!!!!!!!!!!!

  • At 7 March 2013, 2:19:38 user thilanka wrote:   [reply @ thilanka]
    • nice and simple explanation understood very well thank you sir.

  • At 28 February 2013, 15:51:08 user Mystique wrote:   [reply @ Mystique]
    • thank u so much for the awesome explaination it really helped me alot

  • At 23 February 2013, 5:18:56 user sram wrote:   [reply @ sram]
    • super

  • At 22 February 2013, 11:25:15 user Jayapriya wrote:   [reply @ Jayapriya]
    • Nice explanation

  • At 20 February 2013, 14:37:17 user vijay patel wrote:   [reply @ vijay patel]
    • thanks for giving the article.
      sir pls give me how many types of relay available in market with images pls reply me as fast as possible.

  • At 22 January 2013, 11:18:00 user Amit Arora wrote:   [reply @ Amit Arora]
    • i dont think there is a better way to make some one understand the relay operation...thankyou very much it was very helpful

  • At 16 January 2013, 12:03:12 user sourajit wrote:   [reply @ sourajit]
    • We can easily understand how Relay Work to study the chapter.

  • At 29 December 2012, 6:50:04 user swamy wrote:   [reply @ swamy]
    • great explanation.which had given a good idea about it.i hope more component explanation from u...thanq

  • At 28 December 2012, 18:17:07 user suresh kotgire wrote:   [reply @ suresh kotgire]
    • good one,really explained in a simple language with a detailled diagram.

  • At 26 December 2012, 9:45:18 user Mangesh wrote:   [reply @ Mangesh]
    • gr8 explanation with the concept.....nicely understood....thanx

  • At 23 December 2012, 15:26:49 user Aaron Chen wrote:   [reply @ Aaron Chen]
    • your explanation really help me understand what is relay about, I want to unerstand it from long time ago, but I just can't find other source that can help me understand easily like this!

  • At 20 December 2012, 16:02:02 user virendra wrote:   [reply @ virendra]
    • very nice explanation of relay operation

      Thanks Dear

  • At 6 December 2012, 7:53:21 user Harish wrote:   [reply @ Harish]
    • excellent explanation. finally understood the principle behind relays, and now it appears so simple!! keep up the good work.

  • At 3 December 2012, 7:10:28 user Etaa wrote:   [reply @ Etaa]
    • i thank you my fine sir. that was truly a good explanation. that clear everything up. your explanation and diagrams, true genius

  • At 21 November 2012, 6:34:16 user karthik wrote:   [reply @ karthik]
    • super explanation

  • At 20 November 2012, 2:25:41 user Prabhakar Kumar wrote:   [reply @ Prabhakar Kumar]
    • You are amazing .Very clear explanation with illustrative example.
      Thank you and keep on it............

  • At 17 November 2012, 18:06:41 user saiden ayob wrote:   [reply @ saiden ayob]
    • very nice demo... Excellent....

  • At 2 November 2012, 8:52:31 user Sinith wrote:   [reply @ Sinith]
    • Marvelous work ||||

  • At 11 October 2012, 11:25:26 user Binomon Abraham wrote:   [reply @ Binomon Abraham]
    • Nice & simple explanation. Very good


  • At 29 September 2012, 9:53:31 user Mohamad Hilman Bin Ismail wrote:   [reply @ Mohamad Hilman Bin Ismail]
    • thanx 4 your explanation,proud to be an engineer..
      no doubt to take this course

  • At 28 September 2012, 10:34:48 user aniket wrote:   [reply @ aniket]
    • super like...!!

  • At 28 September 2012, 1:25:37 user krishna wrote:   [reply @ krishna]
    • its simply so beautiful i never expected such a beautiful answer from internet

  • At 25 September 2012, 16:00:50 user siri wrote:   [reply @ siri]
    • thank u so much... very useful to understand basic concepts of my small project

  • At 25 September 2012, 11:02:50 user Bhagwati wrote:   [reply @ Bhagwati]
    • good for knowlede

  • At 16 September 2012, 14:37:35 user Ansari yasar wrote:   [reply @ Ansari yasar]
    • Its too benifitial

  • At 9 September 2012, 17:56:34 user ajit wrote:   [reply @ ajit]
    • its too good

  • At 22 August 2012, 22:08:49 user Abe kaate wrote:   [reply @ Abe kaate]
    • good lesson with simple illustrations

  • At 14 August 2012, 21:13:58 user hari rana wrote:   [reply @ hari rana]
    • really informative..very easy to understand.. thanks

  • At 1 August 2012, 13:38:39 user sarang wrote:   [reply @ sarang]
    • grt explanation...

  • At 29 July 2012, 12:21:42 user dayalraj wrote:   [reply @ dayalraj]
    • sir,
      i also want to know about "limit switch" and its operation

  • At 28 July 2012, 4:50:58 user jesu wrote:   [reply @ jesu]
    • super sir thank you a lot... need more from your side

  • At 26 July 2012, 7:17:32 user T.dayalraj wrote:   [reply @ T.dayalraj]
    • i am a lecturer in a polytechnic. Now i can explain this relay topic in such a easy way to the students. i trust that every student can understand this topic about relay.

  • At 18 July 2012, 8:16:22 user shubham wrote:   [reply @ shubham]
    • Grate..........best tutorial of relays

  • At 3 July 2012, 8:13:46 user Giorgos Lazaridis wrote:   [reply @ Giorgos Lazaridis]
    • @Mohammad Nofal Yes you can do that,that is what they are designed for. The coil is completely isolated from the contacts

  • At 3 July 2012, 7:43:48 user Mohammad Nofal wrote:   [reply @ Mohammad Nofal]
    • can we use two loads in the same relay output, one in NO & 2nd one in NC, does the relay coil or sping affected after several times of activation.

  • At 25 June 2012, 12:25:55 user prasanna m r wrote:   [reply @ prasanna m r]
    • superb! solved all my confusions

  • At 7 June 2012, 9:08:16 user muhammad imran mehdi wrote:   [reply @ muhammad imran mehdi]
    • well done very nice description

  • At 28 May 2012, 14:21:06 user cabdikilaas wrote:   [reply @ cabdikilaas]
    • thank u very much so that these way is helpeful procces that can understand every one life over the world or use these technical

  • At 25 May 2012, 5:42:25 user Dhruv solanki wrote:   [reply @ Dhruv solanki]
    • yeeeee it's very good

  • At 22 May 2012, 6:08:12 user mangesh wrote:   [reply @ mangesh]
    • best tutorial of relays

  • At 26 April 2012, 14:22:58 user edresym wrote:   [reply @ edresym]
    • very nice discription

  • At 25 April 2012, 9:14:27 user rizwan iftikhar wrote:   [reply @ rizwan iftikhar]
    • so nice description sir ...... and please describe other electronic component like this one in detail and graphically.......

  • At 17 April 2012, 10:04:53 user vinay wrote:   [reply @ vinay]
    • u explained it very easily

  • At 15 April 2012, 16:53:55 user Sandeep wrote:   [reply @ Sandeep]
    • Very good post...... Thank u very much......

  • At 8 April 2012, 7:51:55 user Muhammad Nasir wrote:   [reply @ Muhammad Nasir]
    • very easy to understand and excellent step wise approach, thnx

  • At 1 April 2012, 6:43:01 user hari wrote:   [reply @ hari]
    • thanx it was good.......and its language.is easy.......

  • At 31 March 2012, 6:06:42 user A. Rafay Inayet wrote:   [reply @ A. Rafay Inayet]
    • The way of Explaining is excellent. It will be more helpful for beginners as well.

  • At 27 February 2012, 11:21:53 user Giorgos Lazaridis wrote:   [reply @ Giorgos Lazaridis]
    • @shahzad you will need to use a transformer to convert 220 to 12. google for "ac/ac transformer"

  • At 27 February 2012, 10:48:54 user shahzad wrote:   [reply @ shahzad]
    • how can i operate relay with 220v
      and how can i convert 220v into 12v bc for relay operate

  • At 8 February 2012, 12:04:43 user Lineo wrote:   [reply @ Lineo]
    • I would like to have theory of 110V DC monitoring relays.How does it work when it monitors that Voltage does not drop and if it does send an alarm?

  • At 23 January 2012, 9:48:14 user adithyan wrote:   [reply @ adithyan]
    • thank u friend..,it helped me alot....

  • At 15 January 2012, 9:31:58 user jyothirmai wrote:   [reply @ jyothirmai]
    • thank you for giving this information,it is easy to learn and nice explanation..........

  • At 7 December 2011, 15:12:48 user krishna wrote:   [reply @ krishna]
    • nice explanation Thank u very much

  • At 12 November 2011, 12:36:02 user Kammenos wrote:   [reply @ Kammenos]
    • @John Miller the latching relay

  • At 12 November 2011, 5:51:46 user zahid wrote:   [reply @ zahid]
    • really nice animation for understanding the basic concept of relay.

  • At 11 November 2011, 17:00:58 user John Miller wrote:   [reply @ John Miller]
    • What type relay DPDT will remain in either position without the coil energized.

  • At 8 November 2011, 16:45:31 user Rakesh Bhati wrote:   [reply @ Rakesh Bhati]
    • Animated working is really very helpful to understand the basic concept of any mechanism....thanks for making this website...,,,

  • At 26 October 2011, 11:51:48 user sujit wrote:   [reply @ sujit]
    • Really, Really......Thank u

  • At 26 October 2011, 9:14:15 user shreyas wrote:   [reply @ shreyas]
    • really good work...helped me a lot.

  • At 23 October 2011, 5:58:26 user Aniruddh wrote:   [reply @ Aniruddh]
    • Its a good presentation. I have understood a lots of things from this website...Keep it up....

  • At 12 October 2011, 10:09:48 user Ziyanal wrote:   [reply @ Ziyanal]
    • ya buddy, very nice....wish you would have been my teacher during my college days...thanks a lot

  • At 11 October 2011, 14:46:42 user hsb wrote:   [reply @ hsb]
    • excellent explanation !!! keep more coming
      thanx !!

  • At 20 September 2011, 12:02:52 user pavithra.s wrote:   [reply @ pavithra.s]
    • really i like this of explanation.if we are reading in book.we can,t understand fully.sometimes it will be confusing.if we read the operations of instruments on animation,it will be usefull.so you have a good sense.please continue this.

  • At 7 September 2011, 8:39:39 user sushil wrote:   [reply @ sushil]
    • Really nice explanation.One of the simplest explanations for understanding relays

  • At 3 September 2011, 10:15:12 user Prashant wrote:   [reply @ Prashant]
    • Very easy explanation,Thanks

  • At 26 August 2011, 13:55:02 user ram wrote:   [reply @ ram]
    • thank you for giving this information,it is easy to learn

  • At 26 July 2011, 3:30:35 user krish wrote:   [reply @ krish]
    • Thanks a lot. What an clear/ excellent explanation...

  • At 3 July 2011, 8:36:38 user ilavarasan wrote:   [reply @ ilavarasan]
    • this is the excellent explanation, thanks

  • At 22 February 2011, 12:21:15 user Rasmi Ranjan Nayak wrote:   [reply @ Rasmi Ranjan Nayak]
    • Hello,
      This is one of the best informative pictorial representation I have ever seen. The flow is very coherent.

      Thanks Buddy.... Keep it Upppppp

  • At 12 November 2010, 11:33:46 user Gangat Mohsin... wrote:   [reply @ Gangat Mohsin...]
    • Thank you for the serail flow for the process in detail......

  • At 28 June 2010, 19:01:31 user ravi wrote:   [reply @ ravi]
    • i like the way you discuss i really thankful that i got such a gud explanation. but i would like to request to discuss more on induction motor for industrial application.

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