multipurpose J-K flip-flop circuit using an SN74LS109AJ

Since the new year, I have been working on setting up a maker space in my garage.  It’s coming along pretty good.  I set up some lights and receptacles on my existing utility counter top, and extended my wired network to a wall-mounted rack where I have some of my networking lab already installed.

home maker space
My home maker space

While organizing my tools and components, I came across a bunch of different IC’s that I didn’t know I had like the 74LS109AJ dual J-K-not flip-flop.

SN74LS109AF dual JK filp-flop
SN74LS109AF dual JK filp-flop

These can be very useful for a number of applications.  Back in school,  I used several of these in tandem to increment memory addresses in EEPROM’s.  Here is a small example of such a circuit using the 555 timer circuit I recently built.

JK flip flop truth table
JK flip flop truth table

Basically, I wired up the IC to toggle.  I used the output of the 555 astable multivibrator circuit as clk input to filp-flop one, and then had Q1 as input to flip-flop two.  It basically divides the frequency of the 555 twice.

555 timer and JK flip-flop breadboard
555 timer and JK flip-flop breadboard
binary counter with 555 and JK flip-flop
frequency divider with 555 and JK flip-flop

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