3-31
Figure 3-21.—Current and voltage in a two-input adder.
An adder circuit is not restricted to two inputs. By adding resistors in parallel to the input terminals,
any number of inputs can be used. The adder circuit will always produce an output that is equal to the
sum of the input signals but opposite in polarity. Figure 3-22 shows a five-input adder circuit with
voltages and currents indicated.
