# RS flip-flop | definition and working principle

## What is RS flip-flop?

the working principle of RS flip-flop. In the previous post I discussed about the definition and types of flip-flop. One type of flip-flop is RS flip-flop so in this article I will discuss about RS flip-flop such as how does RS flip-flop work, how to make RS flip-flop using nand gate and so on

Do you know what is RS flip-flop? The RS flip-flop is a digital circuit that function is to store binary numbers temporarily as long as the current source is unbroken

when the current is interrupted the data stored on the flip-flop will be lost

Need you know Flip-flops can be created by arranging 2 logical gates nand or nor in such a way as to store binary number bits

The way the flip-flop RS is saving bits via the set (S) button and resetting the bits via the reset button (R)

## How to make RS flip-flop using nand gates?

in this article I will show you how to make RS flip-flop using nand gates so must read also article nand logic gate

After that you can making a RS flip-flop using nand gates. The nand gate simbol is as follow

Before creating a flip-flop circuit you must first understand how the nand gate works

The nand gate will output 0 if any input is worth 1

## The nand gate latch circuit

The following circuit is the core circuit of RS flip-flop. RS flip-flop can be made by arranging 2 nand gates or often called Nand Gate Latch

The nand gate latch is the base of the flip-flop. The functions of each on the above is as follows

• Pin S. pin S function to set the value of Q from 0 to 1 (the process of entering data)
• Pin R. Pin R function to reset the value of Q from 1 to 0 (data deletion process)
• Pin Q. Pin Q is the output pin of Q ‘.
• Pin Q’ is a complementary output pin that always contradicts the Q value

## how nand gate latch works

The workings of nand gate latch is quite simple to note is that the input pin must remain given conditions such as condition 1 or 0

If you use a switch then you can outsmart by connecting input with negative terminal through 1K resistor (pull down)

when the switch is removed then the input condition will log 0 and when the switch is pressed will log 1

Here’s the pull down resistor scheme. The red wire signifies logic 1 while the purple cable signifies the logic 0 When the switch is not pressed then the output will be connected with negative voltage (logic 0) Furthermore the above output can be connected to the input nand gate Latch or on any input digital circuit

## How does RS flip-flop work?

The figure below shows the RS flip-flop circuit with clock as for Clock function is to block or allow signal to enter on pin R and S

How the RS flip-flop works on the image above the input data will work when the clock signal is logic 1

If the clock signal logic 0 then the data entered on the pins R and S will be disabled or blocked

The working principle of RS flip-flop

In RS flip-flop will happen some conditions as follows

• RS = 0 0. this means no trigger is applied in this case the output value Q retains the last value it has for example the previous Q is a value of 0 then the value of Q will be 0 second
• RS= 0 1. This means a trigger is applied to the input S. this results in flip-flop sets the Q value to 1-third
• RS = 1 0. This means a trigger is applied to input R. This causes the flip-flop to reset and change the output value Q to 0 to 4
• RS = 1 1. This condition is a forbidden condition or indetermined. This condition means applying triggers on both enter S and R at the same time. This is a contradiction because it implies that we seek to obtain Q output simultaneously equal to 1 and equals 0. This is tantamount to stepping on the accelerator and stepping on the brake pedal (unreasonable).

Therefore this is prohibited. But in fact flip-flop RS is not so used because there are other flip-flop that has better properties than RS flip-flop. Read on the article the working principle of D flip-flop

So the article on the working principle of RS flip-flop