Re: [CAD_CAM_EDM_DRO] Re: Opto / relay recommendation

In a message dated 30-May-02 17:11:57 Central Daylight Time, rab@...
writes:

> Would I need to do any additional supporting circuitry or can I
> connect straight to the pins of an IC socket ?

For "TTL logic-levels", the ULN2003 can be used without "input resistors"
(they are built-in). I no longer remember, but I THINK there are NONE in the
ULN2001?

The input resistors in the ULN2004 are higher, and are for, what, 12 V.
input, as one might find, say, on CMOS CD4000 series, with 12 VDC supply?

The printer-port pins #2 through #9 can be connected directly to the "input
pins" of the ULN2003, I think. At least the printer-port pins I have messed
with are + 5VDC to 0 VDC (nom.)

Be very careful, as a "goof" can smoke the IC that "drives" the printer-port,
and it may-well be SOLDERED onto your mother-board, and fixing that can be a
mother...


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