buildscc | 15 Oct 2011 | | tutorials
When using momentary pushbuttons it is common to want to store and then toggle state. There are a couple of ways to do this, for example, you could using a 555 timer, or construct your own latch/flip-flop. However, the 7400 series of integrated circuits has a few nicely packaged D-Type Flip-Flops which are appropriate for switching. The most appropriate is the 74xx74, which is a dual D-type flip flop with inverted and non-inverted outputs. There are other packages like the 74xx174 which is a quad, but you will need to use your own inverter, such as the 74xx04 or 74xx14, to invert the output. Also the packages with more than 4 D-type flip-flops often share a clock, which means that this method of toggling will not work with them.
1 Parts and Tools 2 Lets Put it Together! 2.1 Schematic Diagram 2.2 Step By Step 2.3 Video Tutorial 3 Resources 4 Credits
Christopher Woodall - chris.j.woodall