Inputs & outputs & relays ohmic

Relays are one of very few things that i can find locally. Everything else is a pain, have to order through friends abroad and wait and wait ........ i am to old for that wait $#@@.

rodw wrote:

You would not believe how hard it is to find reasonably priced components here in Australia. The opto22 brand is quite expensive and not easy to find. I did find this one in a pack of 5. au.rs-online.com/web/p/solid-state-relays/8886843/
Very fast switching times way faster than our servo thread.

It says its DC switching and this article says mosfet can switch both AC and DC.
www.omron.com.au/service_support/FAQ/FAQ02243/index.asp

That is a nice part/price/deal. And yes MosFet's can switch AC and DC, with the AC type having 2 mosfet's inside and DC one only a single one. Mosfet's have a diode inside always so that would let half of the sine wave through even when switched off when using AC, that is why they must have 2 of them wired ....contra !
Mosfet's also have the ability to remain opened by themself ( if the gate is not connected to anything, all it takes to open them is a touch ), but that is very easily dealt with, a single resistor between gate and drain will fix that.
Metal Oxide Semiconductor Field Effect Transistor, full name, i use them a lot, i still have plenty of them on some drives i made just to prove how easy and cheap a stepper motor can be run with Linuxcnc, 4 of them drive a motor, nothing more.
@ John
They can also be used for input sensing, it is basically a relay with no moving parts, and much, much faster.