L293D IC is an important integrated circuit used in control of Relay solenoids, DC and stepper Motor. where containing two H-bridge circuit and a separate input supply. This comes in two different package:
1.through-hole
2. SMD package.

In this project  we will give some basic information of this IC such as how it operates and its features. The image below at the left side is how the trough-hole L293D IC looks like and right side we are showing different pin and their functionalities. Please for more information download its datasheet because here we will give only the main functions and features.

Working

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                In case you wish to interface this IC directly with a micro-controller without adding an auxiliary integrated circuit such as LM2803 IC, you will basically need to use some pull-down or up resistor connected to each input control pin (1A, 2A, 3A and 4A) as shown in the circuit diagram below.

The first motor can be controlled only if the 1st pin of the IC is high (Enable pin) and the direction of rotation depend to the state of pin (2 and 7), for the second motor also the principle doesn't changed, first you need to enable by putting the 9th pin high the control the rotation from (10 and 15 pin).

Note: Do not miss to add those pull-down or up resistance !