RE: [CAD_CAM_EDM_DRO] Re: L297/L298

Hi Jan,

Perhaps set up your quoting of messages a bit clearer. I did not write the
fragment below. The credit for that goes to Wayne Gramlich who has a pretty
nice implimentation. All I did was compliment him for posting the entire
thing on his web site.

John Dammeyer

================

> In a message dated 8/4/2006 3:26:02 P.M. Central Daylight Time,
> johnd@... writes:
>
> The L298 is a bi-polar device and consequently generates
> more heat in
> operation than its FET counterparts<<

================

> I think someone should clarify "bipolar" as used here for the
> non-techie
> types:
>
> There are basically TWO realms of semiconductors, those like
> diodes and NPN
> and PNP transistors are called "bipolar;" and the other kind,
> "FET's"
> (Field-Effect Transistors).
>
> This should NOT be confused with "bipolar steppers and
> drivers!" "UNIpolar"
> stepper-drivers have four transistors that alternately connect two
> motor-wires to negative, the positive "always" supplied via
> center-taps in the two
> windings in "UNIpolar" motors.
>
> "BIpolar" motors have two windings with NO center-taps, and
> the two wires
> per winding (four such wires in all) are "fed" positive and
> negative by the
> driver, and this polarity is simply SWAPPED to negative and
> positive,
> respectively, first in ONE winding for ONE step and then in
> the other winding for the
> NEXT step, and so on.
>
> A "Bipolar driver" can be made with EITHER "bipolar" or "FET"
> transistors!
> Sorry if I've confused you all by my poor explanation! JRR
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
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