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PROJECT BASICS
POWER SUPPLY
SENSORS
RELAY
CURRENT BUFFER
WHERE & HOW to USE
HOW it WORKS
BIDIRECTIONAL CURRENT BUFFER
PARALLEL PORT
LEVEL SHIFTER
WIRELESS COMMUNICATION
PROJECT IDEAS
 

 

 

HOW IT WORKS:

When the input signal to the IC ULN 2003 is HIGH, then the output of the IC at the corresponding output pin is LOW. But if input signal to the IC ULN 2003 is LOW, then the output of the IC at the corresponding output pin is HIGH.

Hence in the above circuit, when input at pin 1 is HIGH, then the DC motor would start running as at the positive terminal of motor we have a HIGH and at the negative terminal we have a LOW (pin 16). But if input signal is LOW, the DC motor would not work as we have HIGH at both terminals of the motor.

 

Input at Pin 1

Output at Pin 16

Motor

LOW

HIGH

DOESN’T WORK

HIGH

LOW

RUNS

LIMITATION: Using this kind of buffer we can’t drive the DC motor in both directions without using much extra circuitry. For performing all 3 functions on motor i.e. run clockwise, run anti-clockwise and stop, we can use another IC L293D which is a bi-directional buffer.

 

 

 

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