One Bit Demux

I'm currently doing a project where I need several demultiplexers. I tried finding some, but I couldn't find any through hole ones. I then made a design from a line decoder and a tri-state buffer. It was an expensive design at ~$2 per circuit, without wires. I then looked at the 74244's family (the buffer I was using) and found the 74241. At first I thought it was dumb, but then I realized if I connect the control SPST switch to the buffer controls it will only power 1 buffer at a time. It does this because 1OE is inverted (hence the overline), while 2OE isn't. That means that buffer 1 will be active low, while buffer 2 will be active high. I then put a pulldown resistor on the control line and boom, it was perfect. Using a quick price check on Mouser I found a 1 switch DIP switch for 36¢, a 4.7k resistor for 13¢ and a SN74HC241N for 50¢. This totaled to 99¢ for 1 of each, it would be cheaper if I ordered more of each, but it shows how smart the change was.

I'll see you next time, ender_scythe.

No comments :

Post a Comment