- #1
j777
- 148
- 0
Hello,
I'm designing a circuit with a linear regulator to supply power to an RFID reader. The input to the regulator is 12VDC supplied by an ordinary external AC/DC desktop switching power supply. When I look at the output of the linear regulator with a scope it looks pretty clean except for 50-60hz (approx. 35mV pk-pk) noise. The same noise is present at the output of the desktop power supply so I'm fairly sure it's from the AC line. Should a well designed desktop supply filter this out or is it up to me to use something like an inline AC line filter on the AC input to the desktop supply?
Thanks
I'm designing a circuit with a linear regulator to supply power to an RFID reader. The input to the regulator is 12VDC supplied by an ordinary external AC/DC desktop switching power supply. When I look at the output of the linear regulator with a scope it looks pretty clean except for 50-60hz (approx. 35mV pk-pk) noise. The same noise is present at the output of the desktop power supply so I'm fairly sure it's from the AC line. Should a well designed desktop supply filter this out or is it up to me to use something like an inline AC line filter on the AC input to the desktop supply?
Thanks