The image above shows a thumbnail of the interactive Java applet embedded into this page. Unfortunately, your browser is not Java-aware or Java is disabled in the browser preferences. To start the applet, please enable Java and reload this page. (You might have to restart the browser.)

Circuit Description

This applet shows the internal structure of the 74182 4-bit Carry-Lookahead Generator.

Click the input switches or type the following bindkeys: 'c' for CN/ (active-low carry in), and '1'..'4' for 'X0'..'X3', and '5'..'8' for 'Y0'..'Y3'.

The output signals are calculated in two-level logic as:

  X = X3 + X2 + X1 + X0
  Y = Y3 (X3 + Y2) (X3 + X2 + Y1) (X3 + X2 + X1 + Y0)

  /Cn+x = /(Y0 (X0 + Cn))
  /Cn+y = /(Y1 (X1 + Y0 (X0 + Cn)))
  /Cn+z = /(Y2 (X2 + Y1 (X1 + Y0 (X0 + Cn))))