PC-BASED DC MOTOR SPEED CONTROLLER

PC-BASED DC MOTOR SPEED CONTROLLER - CIRCUIT IDEAS PC-BASED...

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CIRCUIT IDEAS ELECTRONICS FOR YOU JUNE 2004 PC-BASED DC MOTOR SPEED CONTROLLER SANI THEO T his circuit allows you to control the speed of a DC motor (in eight lev- els) from your PC’s parallel port. The PC uses a software program to con- trol the speed of the motor. The motor is connected to the PC through an interface circuit. The interface circuit consists of 1-of-8 decoder IC 74LS138 (IC1), hex inverter ICs 74LS04 (IC2 and IC3), resistor networks, timer IC 555 (IC4) and motor driver transistor SL100 (T1). The decoder IC accepts binary weighted inputs A0, A1 and A2 at pins 1, 2 and 3, respectively. With active-low en- able input pins 4 and 5 of the decoder grounded, it provides eight mutually ex- clusive active-low outputs (Q0 through Q7). These outputs are inverted by hex inverters IC2 and IC3. R. KARTHICK The resistor network comprising pre- sets VR1 through VR8, resistors R1 and R2 and capacitor C1 are the timing com- ponents of timer IC 555 (IC4), which is configured in astable mode. The output of IC4 is a square wave, which is fed to the
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This note was uploaded on 08/24/2011 for the course ECE 231 taught by Professor Damodar during the Spring '10 term at IIT Kanpur.

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PC-BASED DC MOTOR SPEED CONTROLLER - CIRCUIT IDEAS PC-BASED...

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