Hello,
I'm a beginner in electronics, but somehow I have got to make a circuit to drive a relay. So here it goes
My goal is to drive a DPDT relay ( 5V, 106 mA ) so I'm able to switch the current direction in an external coil. I'm using a DAQ and a mosfet.(RFD14N05L)
In order to drive the gate voltage I use the Digital input/output (5V) of the DAQ. When I don't want to switch current direction, the Digital output is off, when I want to swith the current of the coil, I put the Digital output on. (5V)
The source of the mosfet is connected to the USB ground of the DAQ. See the scheme below.
The problem is that it doesn't appear to work. When I put the digital output on ( in order to get 5V on the gate ), and I measure it with a multimeter I only get Vgs = 0.3 mV
also Vds = 5V and Vgd = 4.7V
So clearly there is a problem somewhere, but I really can't find where... so I thought it was time to get some help.
http://tinypic.com/r/1zoksw9/5
I'm a beginner in electronics, but somehow I have got to make a circuit to drive a relay. So here it goes
My goal is to drive a DPDT relay ( 5V, 106 mA ) so I'm able to switch the current direction in an external coil. I'm using a DAQ and a mosfet.(RFD14N05L)
In order to drive the gate voltage I use the Digital input/output (5V) of the DAQ. When I don't want to switch current direction, the Digital output is off, when I want to swith the current of the coil, I put the Digital output on. (5V)
The source of the mosfet is connected to the USB ground of the DAQ. See the scheme below.
The problem is that it doesn't appear to work. When I put the digital output on ( in order to get 5V on the gate ), and I measure it with a multimeter I only get Vgs = 0.3 mV
also Vds = 5V and Vgd = 4.7V
So clearly there is a problem somewhere, but I really can't find where... so I thought it was time to get some help.
Last edited: