S1 changes the selection of the input signals in the circuit shown here. Other type of circuits, such as monostables with sensors, can generate the command. Notice that the circuit is powered from a +5 and -5 V power supply. The circuit is powered following the next procedure: Vdd = 5 V to 15 V; Vss = 0 V, and Vee = -5 to -15 V. The amplitude of the input signals must not exceed the power-supply voltage. The control input [pins 9 and 10] can be connected to other signal sources, such as the output of counters or memory.
