D – Flip-Flop Made With A LM556 Timer

This entry was posted on Sunday, August 23rd, 2009 at 9:19 am and is filed under Digital.


This circuit is a hybrid – D type Flip-Flop that is constructed from an LM556 – Dual Timer integrated circuit. The circuit is essentially a High-Tech and overly expensive version of the classic transistor flip-flop.
Each time the push button switch (S1) is closed the outputs of the timers will reverse so that one is HIGH and the other is LOW and vice versa. As with the D flip-flop the circuit acts as a binary divider.
D – Flip-Flop
The circuit has some output switching time lag due to the RC time constants at the inputs and the different Trigger and Threshold voltage levels of the timers themselves.
This circuit is not very useful but would make a good Push On / Push Off switch circuit and has a reasonably high sink or source output current level.
Source: http://home.cogeco.ca/~rpaisley4/LM555.html#19