Simple Digital Switching System

This circuit can control any one out of 16 devices with the help of two push-to-on switches. An up/down counter acts as a master-controller for the system. A visual indication in the form of LEDs is also available.  IC1 (74LS193) is a presettable up/ down counter. IC2 and IC3 (74LS154) (1of 16 decoder/demultiplexer) perform different functions, i.e. IC2 is used to indicate the channel number while IC3 switches on the selected channel.

Digital Switching System Circuit Diagram :

Before using the circuit, press switch S1 to reset the circuit. Now the circuit is ready to receive the input clock. By pressing pressing switch S2 once, the counter advances by one count. Thus, each pressing of switch S2 enables the counter to advance by one count. Likewise, by pressing switch S3 the counter counts downwards.

The counter provides BCD output. This BCD output is used as address input for IC2 and IC3 to switch one (desired channel) out of sixteen channels by turning on the appropriate triac and the corresponding LED to indicate the selected channel.  The outputs of IC3 are passed through inverter gates (IC4 through IC6) because IC3 provides negative going pulses while for driving the triacs we need positive-going pulses. The high output of inverter gates turn on the npn transistors to drive the triacs. Diodes connected in series with triac gates serve to provide unidirectional current for the gate-drive.

Sorce : www.ecircuitslab.com/2012/08/digital-switching-system.html

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Digital control system applications

Digital Control System is a branch of the control system with continuous time processes in the region associated with the digital controller as the controller of the control elements that control systems and computing discrete time. Depending on requirements, a digital controller can be shaped microcontroller and ASIC to a standard desktop computer. Because the digital computer system is discrete, then the Laplace transform is used in the control system is replaced with the Z-transform. Therefore, you must understand about the concept of continuous time and discrete time concept.

Flow Chart - Digital Control system applications

Digital computer also has a limited precision (See quantization) extra care needed to ensure that errors in the coefficients, A / D conversion, D / A conversion, etc. do not produce unwanted effects or planned.

The application of digital control can easily be done when used in a feedback form. Since the creation of the first digital computer in the early 1940s the price of digital computers has dropped significantly. The reason this is one of the many reasons for the application of digital control systems for the control of the control system. Other reasons:

Flexibile: easy to configure and reconfigure through software

* Scalable: can be set up programs tailored to the limits of memory or storage space at no extra cost

* Adaptable: program parameters can be changed with the times

* Static operation: digital computers are much more susceptible to environmental conditions rather than of capacitors and inductors

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