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General Mach Discussion / Re: Output voltage problem?
« on: October 15, 2010, 04:23:12 AM »
Repeating what has already been said but the computer port was never designed to switch anything more than about 10mA and even then there are conditions attached. You are pretty lucky you got it to work first time round without damaging the port.
One solution is to use an Opto- Coupler, most of these will handle switching currents up to 100mA (which is enough to drive small relays etc.) and I have attached a simple schematic of a typical setup.
Another solution, if you are switching ac loads, is to use a solid state relay as most of these will operate at less than 10mA input and switch ac loads with absolute minimal noise spikes.
Hope this helps.
Tweakie.
One solution is to use an Opto- Coupler, most of these will handle switching currents up to 100mA (which is enough to drive small relays etc.) and I have attached a simple schematic of a typical setup.
Another solution, if you are switching ac loads, is to use a solid state relay as most of these will operate at less than 10mA input and switch ac loads with absolute minimal noise spikes.
Hope this helps.
Tweakie.
