On Fri, 2009-06-26 at 08:36 -0400, Kenneth Lerman wrote: > You might consider putting an "emitter follower" circuit at the output > of your circuit. The NPN Darlington configuration might be appropriate. > http://images.google.com/imgres?imgurl=http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/ietron/darl.gif&imgrefurl=http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/emitfol.html&usg=__YsP5vDTSAyH1_LgPZsUd4Kj7csk=&h=256&w=248&sz=2&hl=en&start=6&um=1&tbnid=9O8nEjwky6glcM:&tbnh=111&tbnw=108&prev=/images%3Fq%3Demitter%2Bfollower%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DX%26um%3D1 > > Ken
I didn't think I needed a buffer because the LCT1257 can sink or source 60mA and the VFD control input has a high impedance, but now you have me thinking that this may be a bad assumption. I need to figure out the VFD control signal impedance and study the DAC to figure out what it will actually drive. Either way, a 2n3904 is much less expensive than a DAC. One concern is, how much error will be introduced? Although I guess when I add a spindle encoder, the error will be corrected. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
