How to design a Flip Flop using 555 Timer ?

[Lijo George]

Please guide me to design a flip flop using 555 timer. It is a first year college assignment.

 

[Sajo Joseph]

Hi Lijo,

Flip flop is same as Bistable Multivibrator which very easy. It is a tricky question to misguide you.

A bistable can set or reset the output by external pulse, which means that you can store 1 bit digital data. That is same as a flip flop.

You can try this link for more details : Bistable Multivibrator using 555 Timer

 

[Colin Mitchell]

Flip Flop is the broad name for 3 different types of circuits.
They are
monostable flip flop (one state for a short period of time and then reverts back to its stable state)
Bistable flip flop and (two stable states that must be activated into each state)
Astable flip flop. (the circuit constantly changes from one state to the other without the need for any input)

The 555 can be configured to create these three different FLIP FLOPS.

 

[BobK]

That is not the usual terminology. A flip flop is a bistable multivibrator. There are also monostable and astable multivibrators, but not monostable and bistable flip flops.

Bob

 

[Colin Mitchell]

"There are also monostable and astable multivibrators, but not monostable and bistable flip flops. "

How would you know ?????

 

[AnalogKid]

Maybe because English is his first language. The term "multivibrator" was coined because the inventors of the two-tube circuit knew that a square wave contains multiple harmonic frequencies.

https://en.wikipedia.org/wiki/Multivibrator

After that, things get a bit fuzzy. Still, I think the terminology has stabilized to the point that a flip flop is generally viewed as a latch, something that uses feedback to assume one of two stable states when its inputs are stable, as opposed to an astable anything, something thing that does not sit in a stable state with stable inputs.

In the middle is the monostable multivibrator, called so because at its core it is the original cross-coupled astable circuit, but with only one (mono) output cycle instead of continuous oscillation.

ak

 

[BobK]

"There are also monostable and astable multivibrators, but not monostable and bistable flip flops. "

How would you know ?????

Because I have been familiar with this terminology for at least 40 years. And I checked Wikipedia for the definition of flip flop currently accepted.

Bob

 

[(*steve*)]

Surprisingly enough I agree with Colin.

But I also agree with Bob.

When I think flip-flop, I immediately think SR (like the one in a 555), JK, or D? (and yeah, I know there's more. Pretty much by definition these are inherently bistable. Note that the 4047 is described as a multivibrator rather than a flip-flop.

Monostable, bistable, and astable refer to a circuit with 2 states (although, why not 3 or more?) and describes the operation when in one state or the other.

There's a lot of overlap between the two, and I feel the terms are often used rather too loosely. I wouldn't doubt someone will demonstrate this by finding a 4047 datasheet with the word(s) "flip-flop" in the description of the device.

It's probably a bit "pot-ay-toe, pot-ah-toe", and no matter what I prefer, people are always going to get it wrong about 50% of the time .

My first thought when reading the original question was "you don't have to. Look at the block diagram of the 555 because there's an SR flip flop in there."