13 March 2010
Author: Giorgos Lazaridis
How Relays Work Relay Symbols and Characteristics The relay symbols are unlimited. Each manufacturer can make his own symbol for a specific relay that has different internal connections and characteristics, carrying out a specific task. I will illustrate the most basic types of relays:
Relay Characteristics A sample of a label from a relay The things that characterizes a relay are the followings:
The coil voltage: This is the voltage that the coil can actuate the armature. This value should indicate also if the current is AC or DCThe coil current: This value indicates the current that the coil will draw when it is powered with the indicated coil voltage. Very important characteristic to take into account when designing the driver of the relay. The current that goes through the driver must be enough to actuate the armature.The off-voltage: This characteristic shows the minimum voltage that the armature is pulled by the electromagnet. If the voltage goes bellow this value, the spring will overcome the magnetic force and the relay will change state.The number/type of contacts: Is it an SPST? An DPST? DPDT? Or what?The power for the contacts: This characteristic indicates the maximum power that the contacts can handle. Some manufacturers will use the voltage and the amperes, some others the voltage and the kilo-watts, while some others will indicate all three values.The operating temperature: The temperature that the relay can operate without problemsSwitching frequency: The maximum make-break frequencyThe package: Last but not least is the package. Some packages (like the octal type) comes with an appropriate base, while some others are directly soldered/connected to the PCB/electric cabinet.
Basic Relay Operation Looking inside the relay Relay Types Relay Symbols and Characteristics Comments At 21 May 2013, 8:22:39 user salik [reply @ salik] thanks brother it was very helpful for me. Nice animations. At 14 May 2013, 2:52:19 user Best [reply @ Best] This is very helpful! Thanks a lot for your efforts! At 10 May 2013, 4:46:44 user amol [reply @ amol] very simple to understand and impressive. At 19 April 2013, 19:26:14 user sudeep [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, 14:10:17 user Snehal [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, 3:59:49 user Harry [reply @ Harry] thank you for giving this information,it is easy to learn and nice explanation.... At 10 April 2013, 10:49:12 user Abhijeet [reply @ Abhijeet] good one! very helpful, thanks... At 8 April 2013, 3:04:57 user kanyakumari [reply @ kanyakumari] very good explanation with showing pictures thanks a lot At 5 April 2013, 2:22:27 user Neelam [reply @ Neelam] thanks for giving clear idea about relay. At 29 March 2013, 13:19:17 user Giorgos Lazaridis [reply @ Giorgos Lazaridis] @ashmit maybe you want to control high load with small pushbutton or low voltage At 29 March 2013, 4:31:57 user ashmit [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, 8:32:40 user manoj raut [reply @ manoj raut] That is very good method of understanding of relay opertion . At 19 March 2013, 1:47:06 user saheer [reply @ saheer] Very helpful explanation thank u so much....... At 18 March 2013, 6:01:41 user Mnagesh [reply @ Mnagesh] Can you please explain me what is meant by the "Potential free relays". At 18 March 2013, 2:42:24 user Anusha [reply @ Anusha] At 11 March 2013, 10:47:43 user kiran kumar [reply @ kiran kumar] At 10 March 2013, 11:20:53 user kiran [reply @ kiran] really great!!!! this is so helpful.... At 7 March 2013, 11:56:21 user kimani morgan [reply @ kimani morgan] sent me more ok.!!!!!!!!!!!!!! At 6 March 2013, 18:19:38 user thilanka [reply @ thilanka] nice and simple explanation understood very well thank you sir. At 28 February 2013, 7:51:08 user Mystique [reply @ Mystique] thank u so much for the awesome explaination it really helped me alot At 22 February 2013, 21:18:56 user sram [reply @ sram] At 22 February 2013, 3:25:15 user Jayapriya [reply @ Jayapriya] At 20 February 2013, 6:37:17 user vijay patel [reply @ vijay patel] thanks for giving the article. At 22 January 2013, 3:18:00 user Amit Arora [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, 4:03:12 user sourajit [reply @ sourajit] We can easily understand how Relay Work to study the chapter. At 28 December 2012, 22:50:04 user swamy [reply @ swamy] great explanation.which had given a good idea about it.i hope more component explanation from u...thanq At 28 December 2012, 10:17:07 user suresh kotgire [reply @ suresh kotgire] good one,really explained in a simple language with a detailled diagram. At 26 December 2012, 1:45:18 user Mangesh [reply @ Mangesh] gr8 explanation with the concept.....nicely understood....thanx At 23 December 2012, 7:26:49 user Aaron Chen [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, 8:02:02 user virendra [reply @ virendra] very nice explanation of relay operation At 5 December 2012, 23:53:21 user Harish [reply @ Harish] excellent explanation. finally understood the principle behind relays, and now it appears so simple!! keep up the good work. At 2 December 2012, 23:10:28 user Etaa [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 20 November 2012, 22:34:16 user karthik [reply @ karthik] At 19 November 2012, 18:25:41 user Prabhakar Kumar [reply @ Prabhakar Kumar] You are amazing .Very clear explanation with illustrative example. At 17 November 2012, 10:06:41 user saiden ayob [reply @ saiden ayob] very nice demo... Excellent.... At 2 November 2012, 1:52:31 user Sinith [reply @ Sinith] At 11 October 2012, 4:25:26 user Binomon Abraham [reply @ Binomon Abraham] Nice & simple explanation. Very good At 29 September 2012, 2:53:31 user Mohamad Hilman Bin Ismail [reply @ Mohamad Hilman Bin Ismail] thanx 4 your explanation,proud to be an engineer.. At 28 September 2012, 3:34:48 user aniket [reply @ aniket] At 27 September 2012, 18:25:37 user krishna [reply @ krishna] its simply so beautiful i never expected such a beautiful answer from internet At 25 September 2012, 9:00:50 user siri [reply @ siri] thank u so much... very useful to understand basic concepts of my small project At 25 September 2012, 4:02:50 user Bhagwati [reply @ Bhagwati] At 16 September 2012, 7:37:35 user Ansari yasar [reply @ Ansari yasar] At 9 September 2012, 10:56:34 user ajit [reply @ ajit] At 22 August 2012, 15:08:49 user Abe kaate [reply @ Abe kaate] good lesson with simple illustrations At 14 August 2012, 14:13:58 user hari rana [reply @ hari rana] really informative..very easy to understand.. thanks At 1 August 2012, 6:38:39 user sarang [reply @ sarang] At 29 July 2012, 5:21:42 user dayalraj [reply @ dayalraj] sir, At 27 July 2012, 21:50:58 user jesu [reply @ jesu] super sir thank you a lot... need more from your side At 26 July 2012, 0:17:32 user T.dayalraj [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, 1:16:22 user shubham [reply @ shubham] Grate..........best tutorial of relays At 3 July 2012, 1:13:46 user Giorgos Lazaridis [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, 0:43:48 user Mohammad Nofal [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, 5:25:55 user prasanna m r [reply @ prasanna m r] superb! solved all my confusions At 7 June 2012, 2:08:16 user muhammad imran mehdi [reply @ muhammad imran mehdi] well done very nice description At 28 May 2012, 7:21:06 user cabdikilaas [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 24 May 2012, 22:42:25 user Dhruv solanki [reply @ Dhruv solanki] At 21 May 2012, 23:08:12 user mangesh [reply @ mangesh] At 26 April 2012, 7:22:58 user edresym [reply @ edresym] At 25 April 2012, 2:14:27 user rizwan iftikhar [reply @ rizwan iftikhar] so nice description sir ...... and please describe other electronic component like this one in detail and graphically....... At 17 April 2012, 3:04:53 user vinay [reply @ vinay] u explained it very easily At 15 April 2012, 9:53:55 user Sandeep [reply @ Sandeep] Very good post...... Thank u very much...... At 8 April 2012, 0:51:55 user Muhammad Nasir [reply @ Muhammad Nasir] very easy to understand and excellent step wise approach, thnx At 31 March 2012, 23:43:01 user hari [reply @ hari] thanx it was good.......and its language.is easy....... At 30 March 2012, 23:06:42 user A. Rafay Inayet [reply @ A. Rafay Inayet] The way of Explaining is excellent. It will be more helpful for beginners as well. At 27 February 2012, 3:21:53 user Giorgos Lazaridis [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, 2:48:54 user shahzad [reply @ shahzad] how can i operate relay with 220v At 8 February 2012, 4:04:43 user Lineo [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, 1:48:14 user adithyan [reply @ adithyan] thank u friend..,it helped me alot.... At 15 January 2012, 1:31:58 user jyothirmai [reply @ jyothirmai] thank you for giving this information,it is easy to learn and nice explanation.......... At 7 December 2011, 7:12:48 user krishna [reply @ krishna] nice explanation Thank u very much At 12 November 2011, 4:36:02 user Kammenos [reply @ Kammenos] @John Miller the latching relay At 11 November 2011, 21:51:46 user zahid [reply @ zahid] really nice animation for understanding the basic concept of relay. At 11 November 2011, 9:00:58 user John Miller [reply @ John Miller] What type relay DPDT will remain in either position without the coil energized. At 8 November 2011, 8:45:31 user Rakesh Bhati [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, 4:51:48 user sujit [reply @ sujit] Really, Really......Thank u At 26 October 2011, 2:14:15 user shreyas [reply @ shreyas] really good work...helped me a lot. At 22 October 2011, 22:58:26 user Aniruddh [reply @ Aniruddh] Its a good presentation. I have understood a lots of things from this website...Keep it up.... At 12 October 2011, 3:09:48 user Ziyanal [reply @ Ziyanal] ya buddy, very nice....wish you would have been my teacher during my college days...thanks a lot At 11 October 2011, 7:46:42 user hsb [reply @ hsb] excellent explanation !!! keep more coming At 20 September 2011, 5:02:52 user pavithra.s [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, 1:39:39 user sushil [reply @ sushil] Really nice explanation.One of the simplest explanations for understanding relays At 3 September 2011, 3:15:12 user Prashant [reply @ Prashant] Very easy explanation,Thanks At 26 August 2011, 6:55:02 user ram [reply @ ram] thank you for giving this information,it is easy to learn At 25 July 2011, 20:30:35 user krish [reply @ krish] Thanks a lot. What an clear/ excellent explanation... At 3 July 2011, 1:36:38 user ilavarasan [reply @ ilavarasan] this is the excellent explanation, thanks At 22 February 2011, 4:21:15 user Rasmi Ranjan Nayak [reply @ Rasmi Ranjan Nayak] Hello, At 12 November 2010, 3:33:46 user Gangat Mohsin... [reply @ Gangat Mohsin...] Thank you for the serail flow for the process in detail...... At 28 June 2010, 12:01:31 user ravi [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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