L293D Dual H Bridge

Hey guys,

To my understanding the enable pins ( 1&9) must be high (5V) to operate the corresponding side of the IC. However without anything plugged into the enable pin/s I can still operate the L293D (with or without 5v). I have the Pin 8 and 16 provided with Arduino 5V. Any ideas as I am just concerned if this is how it should be operating. Seems like they are no longer serving any function.

Thank You, Geant

Update!

So this should be consider the disable pin because when ever I i close the circuit to ground it disables any output. So the Enable pins do not need any additional wiring and should be considered NO

Anyone else ran into this?

geant90: To my understanding the enable pins ( 1&9) must be high (5V) to operate the corresponding side of the IC. However without anything plugged into the enable pin/s I can still operate the L293D (with or without 5v).

Since 1 and 9 are enable pin . They should be HIGH (+5v) to run the motor at Max rated speed . In general these pins are used to control RPM of the motors. If you give a PWM( Pulse Width Modulation) wave to these pins, motor will run based on the duty cycle. You are leaving those pins floating ,so they should be having some voltage . So they are working , but not at max speed. If you ground them motor won't run.

geant90: I have the Pin 8 and 16 provided with Arduino 5V. Any ideas as I am just concerned if this is how it should be operating. Seems like they are no longer serving any function.

There is no purpose in connecting pin 8 to arduino 5V. Instead you can directly drive motor from arduino pins. Since arduino has little driving or sinking current capabilities you are using L293D. Connect pin 16 to arduino 5v but you have to connect pin 8 to a external supply which can supply rated motor current. Both grounds common.