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I'm new to electronics as a hobby and have just designed a circuit (so please let me know if there's anything else in this circuit wrong) that uses an H-bridge motor driver to control 2 motors. I've read somewhere that I should use a capacitor and a diode to protect the Arduino from current travelling back through the circuit (?), but I'm not sure whether I need one here or if this is the right way to do it if I do need one? Thanks in advance for any help.

Circuit in Tinkercad

Schematic

jsotola
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Ewan
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  • The way you have those diodes connected will allow the motors to be powered in one direction, but in the other direction the diodes will effectively 'short out' the motor driver. – brhans Aug 09 '23 at 06:45
  • The general rule of thumb for all IC is to always provide a decoupling cap close to the supply pin. 100nF unless otherwise specified. – Lundin Aug 09 '23 at 11:17

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Capacitors, no; diodes, yes. The datasheet shows you how to connect the diodes for bidirectional motor control on the left side of the schematic on page 7. You can see they shunt positive spikes above the power supply voltage to the positive rail and negative spikes to (technically, from) ground. The diodes should be Schottky or similar high speed diodes rated for at least the normal operating current of the motor. If you are using the L293D version these diodes are included internally to the chip and do not need to be added.

vir
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