Re: Can I do this with a uProcessor?



tempus fugit wrote:

"Eeyore" wrote:
tempus fugit wrote:
Joseph2k wrote:

What i do not understand is the idea of using ramps to drive relays,
they work much better with on-off control drive. I also have issues
with
using relays at all, electronic switching is faster and quieter.

It isn't the relays I want to ramp, it's the relay drivers.

But what benefit do you expect to get from this ?

Graham

Well, supposedly a capacitative click can be introduced to the audio when
switching using non-mechanical switches,

Like fet switches ? It's 'charge injection' usually. Jfets don't exhibit this
effect like CMOS swiches, although there is another way they can click but this
can be reduced by driving them carefully. Do you recall these were the type I
originally recommended ?


which in this case I suppose my relay drivers (darlington pair transistors)
technically are.

Absolutely not. No connection in any way whatever. Transistors themselves won't
click.


Not being suire of the limitations of the micros, I thought maybe you could
just program a ramped up voltage as the desired output.

Only if it has a D-A output but you can get a ramp of sorts with an R and a C
anyway.

Beware that relays click too, not just from the contacts opening and closing and
the effect this has on any currents but also as the result of induction from the
magnetic field from the coil. The magnetic field problem *can* be reduced by
ramping the *coil current* though.

Graham


.

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