REPLACING OF LATCHING SWITCHES

crutschow

Joined Mar 14, 2008
27,408
Below is the LTspice simulation of an alternate action circuit which uses a CD4013 CMOS FF that changes state every time the push-button is pressed to alternately light the LED D1.

upload_2016-8-25_12-19-44.png
 

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MaxHeadRoom

Joined Jul 18, 2013
23,347
Thank you for u r reply @crustschow.
My requirement is when i press the push button(Tack tile ) led will ON.And if press once again Led will be in OFF state.
Why not use a maintained P.B.?
Push on- Push off?
You can also do it with a relay circuit flip-flop using a momentary P.B..
Max.
 

Thread Starter

Nanda Kumar 1

Joined Aug 25, 2016
40
Below is the LTspice simulation of an alternate action circuit which uses a CD4013 CMOS FF that changes state every time the push-button is pressed to alternately light the LED D1.

View attachment 110992
Thank you Crustschow.Circuit is working fine ,I checked with simulation. If i want to contol 7 leds with different 7 tactile switches ? For these i want to use single ic or 7 number of CD4013?
 

Thread Starter

Nanda Kumar 1

Joined Aug 25, 2016
40
Why not use a maintained P.B.?
Push on- Push off?
You can also do it with a relay circuit flip-flop using a momentary P.B..
Max.
Hi MaxHeadRoom , thank you for u r reply . Presently iam using same (maintained P.B). I want to eliminate using of maintained P.B ,because some time mechanical switch will give problem. so i thought use simple tactile switch with latch circuit.
 

Kjeldgaard

Joined Apr 7, 2016
451
If the D flip / flop circuit to be realized, then it may be easiest to use a MOS 4013 with Schmitt Trigger Clock Input, such as NXP HEF4013.
Then it requires only a pull down resistor and a R/C filter to get a safe switching the output.
 

AnalogKid

Joined Aug 1, 2013
9,287
The circuit you are after is called a toggle or T flipflop. Most general purpose J-K or D flipflop chips can be configured to do this. You also can do it with a hex inverter or any other inverting logic gate like a quad NAND or quad NOR chip. Search for 'toggle flip flop circuit' and you will get many schematics. Here is a 2-transistor circuit I lifted from somewhere in the past. Replace the LOAD resistor with a resistor and LED. You can delete the RESET switch.

Transistors = 2N7000 or 2N7002
No need for 1% tolerance resistors. 5% or 10% will work fine.

ak
Toggle-1-c.gif
 

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MaxHeadRoom

Joined Jul 18, 2013
23,347
I want to eliminate using of maintained P.B ,because some time mechanical switch will give problem. so i thought use simple tactile switch with latch circuit.
Not if you use an industrial version, Telemecanique etc, and also if you wish to reduce any load on the switch contacts, a small simple relay would do it.
Or use the single switch to operate a Mosfet direct.
Max.
 
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