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Adafruit 16-channel PWM/Servo Shield 5V power
Moderators: adafruit_support_bill, adafruit

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Adafruit 16-channel PWM/Servo Shield 5V power

by BPerry on Tue Aug 11, 2020 10:26 am

I am using your 16-Channel PWM/Servo Shield and am using a 12V power supply with a 7805 +5V Voltage regulator to feed the servos through the 2-pin terminal block. The servos are set to maintain either a 0 degree or 90 degree position and are not moving often. Is it better to use a dedicated +5V power supply or to keep using the 7805 Voltage regulator?

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Re: Adafruit 16-channel PWM/Servo Shield 5V power

by adafruit_support_bill on Tue Aug 11, 2020 10:36 am

Definitely better to use a dedicated 5v supply. The 7805 is a rather inefficient 'linear' type regulator which sort of acts like a smart variable resistor. Any excess voltage gets dissipated as heat. So with a 12v supply you are throwing away 60% of your power.

Another option would be to use a 'buck' type regulator. These are much more efficient than linear regulators. Usually > 90%.
https://www.adafruit.com/product/1385

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Re: Adafruit 16-channel PWM/Servo Shield 5V power

by dastels on Tue Aug 11, 2020 10:43 am

As stated in the guide, servos can take quite a bit of current when moving. As Bill says, the 7805 isn't very efficient. More importantly it's relatively low current, with peak output being just over 2A. Depending on usage patterns, that will be adequate. I.e. at most one or two moving at a time. My choice, if possible, would be to use a higher current 5v supply.

Dave

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Re: Adafruit 16-channel PWM/Servo Shield 5V power

by BPerry on Tue Aug 11, 2020 10:59 am

Thanks for the advice. I'll order a dedicated 5V power supply.

BPerry
 
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Joined: Mon Aug 10, 2020 5:53 pm

Please be positive and constructive with your questions and comments.