Testing J-K Flip Flop - HCF4027BE

Thread Starter

PsySc0rpi0n

Joined Mar 4, 2014
1,446
Hi...

I wanted to check if a couple of flip flops I have here are working properly. To accomplish that I was trying to verify the truth table but I'm having some issues in understanding how this works.

What I already did was to check the datasheet which is here.

In terms of connections I have the following:

Pin 16 (VDD) --> 12V DC
Pin 8 (VSS) --> GND
Pin 13 (CLK1) --> 100Hz Arduino square signal with 5V of amplitude

Now, the truth table works with J1 and K1 pins and will set Q1 and not Q1 to 0 or 1, accordingly, no??? Is that it?
 

bertus

Joined Apr 5, 2008
20,568
Hello,

The amplitude of the clock signal needs to be almost as high as the powersupply.
In your case the powersupply is 12 Volts, but the clocksignal is only 5 Volts.
Either amplify the clocksignal to about 12 Volts or use a supply voltage of 5 Volts.

Bertus
 

Thread Starter

PsySc0rpi0n

Joined Mar 4, 2014
1,446
Ok, I already changed it to around 5V.

So, the first state:
J1 -- GND
K1 -- GND

I have
Q1 -- ~5V
not Q1 -- "moving" square wave and after some time it changes to ~5V DC. Can't figure out why it changes to a "moving" square wave.

--------------------------------------
J1 -- GND
K1 -- 5V DC

Q1 -- ~5V
not Q1 -- "moving" square wave and after some time it changes to ~5V DC. Can't figure out why it changes to a "moving" square wave.
--------------------------------------

J1 -- 5V DC
K1 -- GND

Q1 -- ~5V
not Q1 -- "moving" square wave and after some time it changes to ~5V DC. Can't figure out why it changes to a "moving" square wave.
--------------------------------------

J1 -- 5V DC
K1 -- 5V DC

Q1 -- ~5V
not Q1 -- "moving" square wave and after some time it changes to ~5V DC. Can't figure out why it changes to a "moving" square wave.
--------------------------------------

I have no idea why this is happening... I can post a video or some pics to show it!
 

Thread Starter

PsySc0rpi0n

Joined Mar 4, 2014
1,446
J1 -- 5V
K1 - floating/not connected
S1 - 0V
R1 - 0V

Q1 - square wave form
not Q1 - square wave form (when Q1 is high, not Q1 is low and vice-versa)

DS1Z_QuickPrint11.png
 
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