It also enables the connection when the logic signal will be High (1). Pin 9 Controls the connection between Input 3, Input 4, Output 3 and Output 4. It controls the input and output signals. Pin9 (Enable): Pin 9 is also the same as Pin 1.
If there is High logical signal on enable pin (EN) then there will be input and output between pin 2,3,6 & 7 (Input 1, Output 1, Input 2 & Output 2) It has a major effect on Input and output. Pin1 (Enable): Pin 1 is known as the enable pin.The diagram below shows the pin out of L293D IC: It has also internal “pseudo-Darlington source” which amplifies the input signal to control the high voltage DC motor without any interception. To control the max 600mA amount of current an internal “Darlington transistor sink” installed in it, which could be used to control a large amount of current by providing a small amount of current. Its diodes also save the controlling device and IC from back EMF. It could control any DC motor speed and direction with a voltage range of 4.5 – 36 Volts. It may be small in size, but its power output capacity is higher than our expectation. L293D bridge is controlled by external low voltage signals. H-Bridge is an electrical circuit that enables the load in a bidirectional way. L293D has an internal H-bridge installed for two motors. The Polarity of current can change at any time without affecting the whole IC or any other device in the circuit. L293D provides the continuous bidirectional Direct Current to the Motor. It is a low voltage operating device like other ICs. But if we interchange the connection of the battery by connecting opposite polarity, the DC motor will start rotating in another direction as shown in the simulation below. For instance, if we connect the positive terminal of battery with one terminal and the negative terminal of battery with another terminal of DC motor, it will start rotating in clockwise direction. The polarity of input voltage source determines the direction of rotation of a DC motor. DC Motor Direction ControlĪs you know that in case of DC power supply, there is a concept of polarity such as positive and negative terminals of a battery. Usually, a pulse width modulation technique is used to generate a variable dc voltage from constant dc voltage source. In short, we can control the speed of rotation by giving a variable input voltage to a DC motor. Similarly, if we apply 6 volts, the DC motor will run at its highest rated speed. If we apply 3 volts input, the motor will run at its lowest rated speed. For example, If the operating voltage range of a motor is between 3 – 6 volts. One important point to note here is that if we want to control the speed of a DC motor, we will need to provide a variable voltage to the DC motor. But the voltage should be within the operating voltage range. The higher the input voltage, the higher will be the rotational speed of the motor. The speed of rotation of motors is directly related to the input voltage.
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