Voltage dropping for DC motors

[bcross]

Hi guys,

I am a complete newbie to electronics having brought an Arduino a few months ago and what can I say I'm hooked! Anyway forgive me for my low level of knowledge.

I want to power two DC motors with a 5V source (powering a dual H-bridge IC controller connected to arduino) but according to the datasheet the DC motor is only rated 1.5-3.0V. The H-bridge must be supplied 4.5-36V. I was thinking I could drop the voltage across each motor by placing resistors in series. However (I can't get a decent resistance reading and) I am concerned that the resistors will overheat (burn out). Is it really a bad idea to supply 5v to a 3.0V max rated motor? If so what is the best (also cheap!) way of dropping the output voltage from the H-bridge?

Ben

Motor Datasheet: https://www.pololu.com/file/download/fa_130ra.pdf?file_id=0J11
H-bridge Datasheet: http://www.ti.com/lit/ds/symlink/l293d.pdf

[Zero999]

Don't worry about it. The datasheet says the h-bridge drops a couple of volts so with 5V in, the voltage across the motor will be not much more than 3V.

[langwadt]

Hi guys,

I am a complete newbie to electronics having brought an Arduino a few months ago and what can I say I'm hooked! Anyway forgive me for my low level of knowledge.

I want to power two DC motors with a 5V source (powering a dual H-bridge IC controller connected to arduino) but according to the datasheet the DC motor is only rated 1.5-3.0V. The H-bridge must be supplied 4.5-36V. I was thinking I could drop the voltage across each motor by placing resistors in series. However (I can't get a decent resistance reading and) I am concerned that the resistors will overheat (burn out). Is it really a bad idea to supply 5v to a 3.0V max rated motor? If so what is the best (also cheap!) way of dropping the output voltage from the H-bridge?

Ben

Motor Datasheet: https://www.pololu.com/file/download/fa_130ra.pdf?file_id=0J11
H-bridge Datasheet: http://www.ti.com/lit/ds/symlink/l293d.pdf

An L293 powered by 5V will give you less than 3V  on the motor

look at Voh and Vol on page 5 of data sheet

[bcross]

Brilliant! Thanks guys.