A very simple yet effective electronic toggle flip flop switch circuit can be built around the IC 4017.
By adding just a handful of other passive components the circuit can be made to toggle accurately through subsequent input triggers either manually or electronically.
A couple of very useful flip flop toggle switch circuits are explained here.
They may be operated through external triggers either manually or an electronic stage. Circuit schematics of these flip flop circuits have also been included.
Simple Electronic Toggle Switch Flip Flop Circuit Using IC 4017
We know that in response to every logic high pulse at pin #14, the output pins of the IC 4017 are switched high sequentially from # 3 to # 11 in the order: 3, 4, 2, 7, 1, 5, 6, 9, 10, and 11.
However, this proceeding may be stopped at any instant and repeated by just connecting any of the above pins to the reset pin # 15.
For example (in the present case), pin # 4 of the IC is connected to pin #15, therefore, sequence will be restricted and will bounce back to its initial position (pin # 3) each time the sequence (logic High) reaches pin # 4 and the cycle repeats.
It simply means that now the sequence toggles from pin # 3 to pin # 2 in a back and forth manner constituting a typical flip flop action. The operation of this electronic toggle switch circuit may be further understood as follows:
Every time a positive trigger is applied to the base of T1, it conducts and pulls down pin # 14 of the IC to ground. This brings the IC to a standby position.
The moment the trigger is removed, T1 stops conducting, pin # 14 now instantly receives a positive pulse from R1. The IC acknowledges this as a clock signal and quickly toggles its output from its initial pin #3 to pin #2.
The next pulse produces the same result so that now the output shifts from pin #2 to pin #4, but since pin #4 is connected to reset pin #15, as explained, the situation bounces back to pin #3 (initial point).
Thus the procedure is repeated every time T1 receives a trigger either manually or through an external circuit.
Accurate CMOS Flip Flop Circuit Using IC 4093
Another simple and very accurate flip flop circuit can be made using three gates of IC 4093. Looking at the figure we see that the inputs of N1 and N2 are joined together to form logic inverters, just like NOT gates.
It means that, any logic level applied to their inputs will be inverted at their outputs. Also, these two gates are connected in series to form a latch configuration with the help of a feedback loop via R5.
N1 and N2 will instantly latch the moment it senses a positive trigger at its input. Another gate N3 has been introduced basically to break this latch alternately after every subsequent input pulse.
The functioning of the circuit may be further understood with following explanation:
On receiving a pulse at the trigger input, N1 quickly responds, its output changes state forcing N2 to also change state.
This causes the output of N2 to go high providing a feedback (via R5) to N1’s input and both the gates latch in that position. At this position the output of N2 is locked at logic high, the preceding control circuit activates the relay and the connected load.
The high output also slowly charges C4, so that now one input of gate N3 becomes high. At this juncture, the other input of N3 is held at logic low by R7.
Now a pulse at the trigger point will make this input also go high momentarily, forcing its output to go low. This will pull the input of N1 to ground via D4, instantly breaking the latch.
This will make the output of N2 to go low, deactivating the transistor and the relay. The circuit is now back to its original state and ready for the next input trigger to repeat the entire procedure.
Parts List for FLIP FLOP CIRCUIT WITH IC 4017
R4 = 10K,
R5 = 100K,
R6, R7 = 4K7,
C6, C7 = 10µF/25V,
C8 = 1000µF/25V,
C10 = 0.1, DISC,
ALL DIODES ARE 1N4007,
IC = 4017,
T1 = BC 547, T2 = BC 557,
IC2 = 7812
TRANSFORMER = 0-12V, 500ma, INPUT AS PER AREA SPECIFICATIONS.
Parts List for FLIP FLOP CIRCUIT WITH IC 4093
R3 = 10K,
R4, R5 = 2M2,
R6, R7 = 39K,
R4, R5 = 0.22, DISC,
C6 = 100µF/25V,
D4, D5 = 1N4148,
T1 = BC 547,
IC = 4093,
Wawoo its working fine now. Thanks so much SWAGATAM realy awesome , i love ur site so much . Now sir for there other circuit for obstacle avoiding robot can i use sm0038 infrared receiver in place of tsop1738? Thanks so much
Glad to know it’s working Davis, yes you can use SM0038, it’s specs are similar to TSOP
Yes SWAGATAM i made changes as u said like output for simple clap switch but now i power on circuit the relay activate and switch on the load before even i triger the circuit. Help me about this
connect pin#15 with ground through a 100K resistor, and connect a 0.22uF or any capacitor below 1uF across pin#15 and the positive line.
Helo SWAGATAM thank for ur great work ,i tried the first circuit with ic4017 above and trigered using an electronic circuit and the load switched on but when i trigered again to switch off the load it refused ,then i powered off the circuit then switched on again and trigered the load switched on but fail to go off for second triger,please help me how to solve this problem .thanks so much
Thanks davis, it could be happening due to voltage spikes at pin#14, which might be forcing the output to randomly bounce to some irrelevant output pinout.
you can try configuring the output of the 4017 through diodes, as shown in the first circuit of this article
https://www.homemade-circuits.com/2011/12/make-simple-electronic-clap-switch.html
dear sir
I am really happy to write you. I have one question about flip -flop Ic 4093.
what is the group number of this ic?
I mean El 4093 or MF 4093 ?
only 4093 can’t find in shop. plz help me. thank you.
Shihab, you just have to say “IC 4093” to the shopkeeper, and you must get it….the initial prefix is not important. If the shopkeeper doesn’t understand then he seriously lacks knowledge, in that case you can yourself check the available options from him and look for the number 4093 on the IC
Sir,
I am a retired person ( 63 running ). I am residing at Howrah, W.B. (Pin code : 711102 ). I have been madly searching for fully solid state automatic voltage stabilizers for my 40' LED TV & LAPTOP ( DELL ). Because of voltage fluctuation, both of my ( previous )Sony make 46" LED, 3D TV as well as the LAPTOP became out of order. The Sony TV could not be repaired by the dealer( Power board not avail able ), but somehow the laptop got repaired. Would you please take the pain to intimate me the address, phone no., approx. cost of 2 nos. fully solid state automatic voltage stabilizers for my 40" LED TV ( Mitashi )& LAPTOP ( DELL ) ? Eagerly waiting for your response. Regards, S. DATTA, e-mail : sdsdatta@gmail.com ( ph. : 0 99030-88252 / 0 89610-44436 )
Hello Mr. Datta,
you can try the following concept for your need
http://www.homemade-circuits.com/2016/05/h-bridge-mains-voltage-stabilizer.html
but please note that this circuit might require an advanced knowledge of electronics for successfully completing it.
Hi. To build 1st ciruit if i have 12v dc suply i think its not necessary to build ic2 section which is nothing but voltage regulation. Tell me if iam wrong. Thanks in advance
yes it won't be necessary if the supply is fairly constant.
Hi sir,
i am Vishnu
i am newer in electronics. last one month i am regularly reading your blogs related with my project.
i require IR remote controlled circuit diagram for home appliances ( 4 lights and 1 Fan ) having memory back up for storing relay state during power failure. could you help me for developing the same. ?
Hi Vishnu, you can try the following concept as explained in the article:
http://www.homemade-circuits.com/2014/05/remote-control-circuit-for-multiple.html
What could be the relay in IC 4093 cct?? means it has the specific value or what? kindly guide me as soon as possible.
the relay could be as required, depending upon the load and the supply voltage for the circuit
Dear Ankit,
I have tested the above circuits thoroughly and they worked perfectly for me, so it would be difficult to understand your circuit problem.
Alternatively you can try the first circuit given in the following link:
https://www.homemade-circuits.com/2011/12/make-simple-electronic-clap-switch.html
Build only the IC1 section, remove T2 and all parts at the left of T2, don't remove R5, change the position of C3 and connect it across pin14 and ground. Now trigering pin14 with positive will produce the required results.
Dear sir,
I made this circuit and its working but problem is every time i connect power supply relay gets on automatically and it doesn't show any activity if i sort triggering wire with positive of my power supply i checked several times connectivity and spare parts too. please help me once again…
Thanks
dear sir i am trying to make the above circuit but i am not able to understand that how i can trigger flip-flop manually to turn relay on/off. please help me out.
Dear Ankit,
Touch the positive supply with the "trigger" point momentarily, everytime you do this the relay will switch ON and OFF alternately.
sir is there a circuit that can control 2 or more devices with single button.. i mean once you press 1 device is ON, second time press 2 device is ON & third time press both are OFF. I want to use this circuit for 3 channel RF remote control circuit that I have got, but I want to control 4 or more devices with that. so 1 channel from my rf remote control receiver have to be connect to the circuit suggested by you. so please help me with this.
it may be done by modifying the first circuit.
Connect another relay driver stage to pin4.
Connect R6 with pin7
positive trigger at the shown input will toggle the load sequentially.
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thanks! please let me know what help you require from me.
Hello
excuse me sir
but in the Accurate CMOS Flip Flop Circuit
Using IC 4093……..d4 in its direction will not allow n3 to do anything on the crkt, it has to be backwards that diode so that the output of n3 affects the crkt, isnt it???. another thing, where is d2 that u mention in the article??
thks in advance 😉