The Quad Gate uses a single quad logic chip and combines them in 4 different ways. 1-A and 1-B are combined and appear at 1-OUT. 2-A and 2-B are combined and appear at 2-OUT. 3-OUT is a combination of 1-A and 2-OUT. 4-OUT is a combination of 1-OUT and 2-A. Any standard quad logic gate IC can be used, for example 4001 NOR, 4011 AND, 4070 XOR.
