Re: [CAD_CAM_EDM_DRO] Detect Stepper pulses

In a message dated 2/12/2004 6:24:20 PM Central Standard Time,
jnr@... writes:
Perhaps an LED on the line would show a glow of signal pulses?
Ray: Perhaps if you select one of the new "efficient" LED's which light
fairly brighly with only 5 mA., wired in series with a 680 ohm or 820 ohm R to
ground, and the "TTL" signal SOURCE you are testing is a BUFFER, or 74HC[T]nnn
type IC, this would work. Or, if you are sure all your signal source is just
old TTL, or "LSTTL", connect the series R to +5, and then when the LED is lit,
the source is "LO", or if "HI", the LED is OFF. This IS kinda a kludge, and
whoever does this "cheap way" must pretty-much have the experience with
breadboarding so that he "KNOWS what he is doing!".


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