Hello! I have this USB-6000 unit which has only 3.3V 4mA digital output. I want to switch a relay by means of MOSFET but so fat the current/voltage capabilities has had no success. I am easily able to it it using any Arduino wiht 5V 20mA out though. Probably lower threshold gate voltage FET would help?Could anyone advise? Except,of course getting a better DAQ.
This reply might be a bit late, but I'll try to help.
Are you wiring the USB-6000 to a circuit board where you want an output wire to switch a relay? In that case, you would want a MOSFET transistor with a threshold of roughly half the maximum output (3.3 / 2 = 1.65). This info should be available on different data sheets for transistors. Do you want to switch on a high or a low voltage?