Hexa decimal counter with 555 - JK Flip flop

381

03:58:52

Using a 555 timer in astable mode, clocking a series of flip flop. This allows the flip flops to count in binary. Lastly a binary to 7-segment decoder is used to give decimal values to a 7-segment.(Potentiometer values and cap valus may be changed at the 555 timer for a faster clock). Also hex value of "A" is decoded using 3 AND gates.

published 5 years ago

wyoelk

5 years ago

Perhaps a different version with a transistor to prevent letters A-F from displaying _ _ http://everycircuit.com/circuit/4642623753814016 _ _

wyoelk

5 years ago

It really isn't counting correctly at all as it keeps displaying the 0 between several digits. I'm not very knowledgeable pn flip flops but something not quite right

maxmax_66

5 years ago

The flip flops don’t toggle simultaneously but rather sequentially. You will notice that switching from even to odd values, there is no issue. However switching from odd to even values causes an issue. The binary value requires only one change, namely the least significant bit, to affect the next sequential representation when going from an even value to an odd one, so that although there is a delay, this single switching causes no problem. In going from odd values to even values, the binary representation requires two or more switching between the zeroes and ones so that because of the delay, other values are displayed as the flip flops toggle sequentially.

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