Set the initial/known state of JK Flip flop

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snvallad

Joined Jun 16, 2021
1
Hi guys, this is my first post. I've been reading this forum for several weeks trying to learn about IC and electronics to make a controller pedal for my guitar pedals. I'm not an engineer, either a profesional musician, but i'm an architect, so electronics its clearly not my field. But I've enjoyed making things and seeing simple circuits finally work. So, the question, i have this JK Master Slave Flip Flop (cd4027be), well, like 6 of them in my project/attempt of circuit, and for what i've been learning, when you power up any storage-memorish-latch IC, it initialize in a indeterminate state, which is a big problem for me, because I don't want to go through each switch, reseting or clearing up all of them. So I found some solutions for this problem, and i think its something called Power-on-reset circuit, but i just don't get it. So I ask you, how can i implement that kind of circuit between A-B (or just modify all the reset circuit) so when I power this up for the first time, the JK flip flop Q output starts after lets say 0,2 or 0,5 seconds in a LOW state, and this circuit or magical IC, still allow me to clear manually with a momentary switch my JK ff when the circuit is working?
Thanks everybody,;)
 

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eetech00

Joined Jun 8, 2013
2,653
Hi

If you want Q high at power on:

1623906161171.png

When power is applied, C1 will begin to charge and short VDD to the set pin and set the Q output high.
When C1 completes charging, the set pin will be close to ground.

If you want Q low at power up, connect this circuit to the reset pin instead of the set pin.
 
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