Current draw question

Taisho

I am confused about current draw on BS2 pins.· I have read the max current draw is 25ma per pin with a max of 50ma for each group of 8 pins.· My question is about the current draw of servos connected to the servo ports on a Board of Education.· I saw one reference saying the continuous rotation servos draw 150ma.· Is that correct?· Does the current draw of the servos count toward the 50ma limit?

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Bruce Bates

Taisho -

The continuous rotation servos may well draw 150 mA, but the Stamp pin ports shouldn't be seeing that current. When a servo is wired up, there are three terminals or wires. One is the + wire, one is the - wire, and the third is the signal wire. ONLY the third (signal) wire is attached to a Stamp pin port. The signal wire carries very little current. The current carrying wires are the other two.

So, as you can now see, the current limit of the Stamp pins port(s) is not affected by a servo, if it is wired correctly. It doesn't matter whether it's a continuous rotation servo or not.

Regards,

Bruce Bates

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Involvement and committment can be best understood by looking at a plate of ham and eggs. The chicken was involved, but the pig was committed. ANON

Taisho

Oh thank you. I was confused. I am being paranoid because I am afraid of cooking my BS2s. I am new to electronics and I'm trying to be careful. Thanks for the help.