Latch using JK Flip Flop

In this post we will learn how to use JK flip flop as a latch. i.e. for one pulse, the circuit continues to stay in the ON state until the next pulse. and the circuit continues to be in the OFF state till the next pulse.
This can be achieved by using toggle mode in JK flip flop.

TRUTH TABLE:

IC 7476

J k set ' reset' Q Q'

1 1 1 1 Toggle

IC CD4026

J k set reset Q Q'

1 1 0 0 Toggle

Note:
Set is referred as PRE or preset.
Reset is referred as CLR or clear.

Refer the Datasheet of the JK flip flop you are using to check whether it is set' and reset' or just set and reset. in the later case you should make set and reset as 0 instead of 1.Example: IC CD4026 has set and reset, whereas IC 7476 has set' and reset'.
Refer the data sheet to check whether the JK flip flop you are using is low-high trigger or high to low. accordingly connect the clock pin to the switch.In this case, the IC7476 is high to low transition. hence a 10k resistor is connected to the clock to keep it high. and a button switch is connected from clk pin to ground. so every time the button is pressed there is a transition from high to low. in case of CD4026, it is a low to high transition.

Circuit diagram:

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