Steren ARD-020 Manual De Instrucciones página 57

The other way is generating PWM signals using the microprocessor capability
through the function digitalWrite ().
If you want to simultaneously control the speed and direction of a motor, we need
to use an integrated circuit or chip, called in general, as " H bridge ", for example
the L293D.
Chip L293D/B (H-bridge):
It is an integrated circuit or chip that can be used to simultaneously control the
speed and direction of two DC motors (containing two H bridges). The difference
between L393D and L293B model is that the fi rst comes with protection diodes
which avoid damage caused by the voltage spikes that the motor can cause.
It contains 4 digital pins (2, 7, 10, 15) to control the motor direction.
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