Okay, so I was messing around with flip flops the other day, trying to come up with some interesting designs. It wasn’t for anything serious, just a bit of fun, really.
First off, I started simple. I remembered seeing this cool idea online about using a couple of NAND gates to make a basic SR flip flop. So, I grabbed some 7400 chips – you know, the classic quad NAND gate IC. I breadboarded it up, wired the inputs, the power, ground, the whole shebang. Hooked up some LEDs to the Q and Q-bar outputs so I could actually see what was going on. Fiddled around with the inputs, and bam! It actually worked. Kinda satisfying seeing it flip and flop like it should.
Then, I thought, “Alright, let’s kick it up a notch.” I wanted to build a D flip flop. So, I cheated a little. I looked up the truth table, and then figured out I could just add a couple more NAND gates to the SR flip flop I already had. This time, instead of directly controlling the set and reset, I used one input as the D (data) and another as the clock. It took a little bit of tweaking with the wiring to get it right – kept getting stuck in some weird states – but eventually, after a bit of head-scratching and re-wiring, it worked! Feeding in the data and watching it latch on the clock pulse? Sweet!
After that, I got a bit ambitious. I wanted to make a JK flip flop. Now, this is where things got a little hairy. JK flip flops are more complicated because they have that “toggle” state where both inputs are high. So, I went back to the internet, did some digging, and found a few different designs using, you guessed it, more NAND gates. I tried a couple of different arrangements, and let me tell you, it was a mess of wires. I must have spent a good hour just trying to get the connections right. One design would kinda work, but then get stuck in a loop, another wouldn’t toggle correctly… it was frustrating.
- Kept double checking my wiring against the diagrams.
- Made sure the NAND gate chips were all properly powered.
- Tried different pull-up resistors on the inputs.
Finally, I found a design that clicked. It used a couple of extra NAND gates to handle the toggle state, creating some feedback loops. I wired it up very carefully this time, double-checking every connection. Flipped the power switch, and…it worked! Jiggled the J and K inputs, pulsed the clock, and it toggled like a charm. I was so stoked.
Of course, all this was just on a breadboard, so it wasn’t exactly practical. But it was a good exercise in logic design. I learned a lot about how flip flops work, and got a bit more comfortable with using NAND gates to build complex circuits. Maybe next time, I’ll try making a counter or something. Who knows?
