Page 51 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

Master-Slave Flip Flop Circuit

• Before knowing more about the master-slave flip flop you have to know more on the basics of a J-K flip flop
and S-R flip flop. To know more about the flip flops, click on the link below.
• Master-slave flip flop is designed using two separate flip flops. Out of these, one acts as the master and the
other as a slave. The figure of a master-slave J-K flip flop is shown below.
• From the below figure you can see that both the J-K flip flops are presented in a series connection. The output
of the master J-K flip flop is fed to the input of the slave J-K flip flop. The output of the slave J-K flip flop is given
as a feedback to the input of the master J-K flip flop. The clock pulse [Clk] is given to the master J-K flip flop
and it is sent through a NOT Gate and thus inverted before passing it to the slave J-K flip flop.

Inputs Outputs Remarks

Case CLK J K Q n+1 Q n+1

X 0 0 Q Q No change
I n n
0 1 Q Q No change
II (1) n n

0 1 0 1 Reset
III
(1)
1 0 1 0 Set
IV
(1)
1 1 Q Q Toggle
V n n
(1)
Counters
A Counter is a device which stores (and sometimes displays) the number of times a particular event or process
has occurred, often in relationship to a clock signal. Counters are used in digital electronics for counting purpose,
they can count specific event happening in the circuit. For example, in UP counter a counter increases count for
every rising edge of clock. Not only counting, a counter can follow the certain sequence based on our design
like any random sequence 0,1,3,2… .They can also be designed with the help of flip flops. They are used as
frequency dividers where the frequency of given pulse waveform is divided. Counters are sequential circuit that
count the number of pulses can be either in binary code or BCD form. The main properties of a counter are timing
, sequencing , and counting.
Counter works in two modes
• Up counter
• Down counter

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CITS : E & H - Electronics Mechanic - Lesson 9 - 29