Re: [CAD_CAM_EDM_DRO] Opto / relay recommendation

Hi Rab,

It sounds like you could use a relay driver approach. use a 7404 IC to
drive a TIP120 transistor through a 2K resistor. the valve is connected
to +24V, and the darlington transistor "pulls" the other lead down to
ground. Much like a simple coil driver used in an inexpensive unipolar
driver (MaxNC board comes to mind). Be sure to put a diode across the
valve's coil for back EMF.

An opto-isolator could be used instead of the IC if desired.

HTH

Alan KM6VV


rainnea wrote:

>
> Hi,
>
> I'd like to connect up some 24V pneumatic valves ( to turn on and off
> some air spindles ) could anyone recommend components ( preferably
> that I can get from Farnels ) that would handle 24V / approx. 100mA
> and can be safely driven from the printer port ?
>
> PS. I am considering using a few valves per spindle in parrallel to
> give some form of air flow / spindle speed control if that make
> sense ?
>
> Thanks,
>
> Rab