My old car uses a 1mA current driven tach movement and the stock circuit isn't compatible with the MSD ignition box I use, and the adapter they sell to make the tach work buzzes like the dickens.
So I worked up a tach circuit based on the current tach diagrams in the LM2907 datasheet that'll...
Once again, I'm stuck on a (likely) not so complex issue but I lack the proper vocabulary to find the answer quickly on Google.
Long story short, I've made a calculator using two, 4-Bit BCD Full adders. The part that this post concerns is in between the Input (0-9 Keypad and Decoder) and the BCD...