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Old 06-07-2004, 08:51 AM   #1
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ko super inductor?

what is the value of this inductor (H)? and is this something that most extensive electronic stores will have?

what is it's fuction and how does it accomplish this? i know of inductors being used as lowpass filters, but typically on ac signals. what is it doing here for our servos?

answers appreciated.
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Old 06-07-2004, 10:18 AM   #2
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Donīt know of a super inductor. But when I bought my KO 7.2V servos some time ago there was an inductor supplied with a value of 4.7 uH. Maybe you mean this?

You only need the inductor if youīre using a 7.2V servo. The nowadays ESCīs are making some highfrequency voltage spikes and the servos donīt like this. The inductor smoothes out these spikes so the servo seeīs a clean voltage. You have to use the inductor between the positive (red) wire of the servo and the positive connector of the battery. Some ESC also have a special wire so you donīt have to solder directly to the battery.

Without the inductor the servo wonīt work as usual but if it really goes bad the servo also could be damaged by the voltage spikes.
But you only need this with a 7.2V servo not with the usual 5V servos.
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Old 06-07-2004, 10:48 AM   #3
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thanks, yeah that covers a bulk of it.

so it damps voltage spikes? only at high frequencies? what about current spikes? i think that to be more variable than voltage? no?
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Old 06-08-2004, 05:44 AM   #4
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I think the way to look at it is throuh ohms law. V=IR doing a little math we see that I=V/R so the current is dependant upon voltage divided resistance. The resistance is pretty constant, so if we control the spikes on the voltage, we control the spikes in the current too. Truthfully, inductors are current limiting devices. SO, we can use the equation again and say that if we control the rate of change of current di/dt, we reduce the amplitude of the voltage spikes. This comes from the basic equation for an inductor V=L*di/dt this means the voltage across an inductor equals the inductance times the rate of change of current. If the rate of change is high as is the case with a spike, the voltage across the inductor will be high. This prevents the spike of voltage from getting to the receiver. So I guess it depends how you look at it. In any case, the inductor will help filter out the junk you dont want
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