Why does WAM warn not to use external power supply on servo?

Tom F

Why does WAM warn not to use external power supply on servo and to use the 9V battery only? Does this apply to all servos, or just some, etc.

Chris Savage

Tom,

·· Many power supplies are unregulated (including those we carry) which means their output voltage can be higher than their rated voltage when not at the rated current draw.· This could possible damage the servo so we offer the warning to prevent you from doing this.· If you have a supply known to be regulated and output exactly 9V you could use it, although when working with the servo 6V or so would be better.· The Board Of Education offers a jumper which lets you select whether the incoming voltage or the regulated 5V goes to the servo.

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Chris Savage
Parallax Tech Support
csavage@parallax.com

Amaral

Well , I think that WAM is part of the STAMP in CLASS, that means ( at least for me ) that all the experiences are for learning.
The BS2 works very well if powered below 9V it can be powered up to 12V but it's not a good ideia. (that's a lot of questions in this foruns regarding this ) . this is not good idea because it causes the regulator do drop a lot of voltage, making it heat itself.

There is a lot of different servos in the market , but especially FUTABA or PARALLAX are rated for 4.8 - 6V ( I'm not sure about this info , please check ) been this way , to avoid burning the STAMP or the servos the WAM BOOK tells you to use a 9V battery or power suply.

This all are just a guessing , i'm not a specialist ( actualy not even close from it ) ( or not ever far from it ) so ...

Amaral.