Re: [CAD_CAM_EDM_DRO] Dumb question on TTL control of a relay from parallel p...

In a message dated 9/9/2003 8:27:40 AM Central Standard Time,
jeff@... writes:

> If the above current is too high, is it best to try to find a
> miniature reed relay to control the coil of the "power relay" or is
> there a better way?
>

Jeff: The ULN2003 has SEVEN Darlingtons, any ONE of which could control
SEVERAL of those relays connected in parallel. A miniature reed-relay might
"theoretically" work (so long as the proper "spark suppression diode" is used
across it), but when controlling heavier loads, SOME very tiny reed-contacts will
WELD. But perhaps not with an INDUCTIVE load? The ULN2003 is a better idea.
An alternative with only TWO "relay drivers" is the 75477 8-pin DIP.


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