power switches for uPs - for computer-controlled d.c. powered equipment

for computer-controlled d.c. powered 373 equipment 374 5V 2001 T2 It is not enough simply to own a micro computer, you must also know what to do with it. Having found an interesting field of application the next question will be "how should it E) be done?". The answer usually in- volves programming input/output cir- cuits, or designing them. This can strike fear into the hearts of many users of computers that have rudimentary, or non-existent, in- put/output facilities. Fortunately, this fear is groundless and, as the circuit here shows, it is not at all difficult to use a computer to drive relays, elec- tronic switches, and all sorts of lamps, motors, or whatever. The basis of this circuit is formed by the eight flip-flops contained in IC1. These are controlled by a positive pulse (for the 74LS373) or a rising edge (74LS374) and ensure that the output logic levels remain stable. The control signal applied to pin 11 could be obtained in several ways, such as via a programmable out...