Hi, * I need to ask if i have a PCB board with analog and digital circuits, is it's right to connect the digital and the analog GND to the GND layer or i must create two Gnd layers and connect them at the Gnd entery point to the board.
* I have another problem with a circuit i have designed uses a linear power supply with a transformer 220-12 VAC 1A , when i measure on any point on the circuit with respect to the earth point i found 110 VAC on the scope. I need to know why i see this 110 VAC or this is due to the transformer interwinding capactance, if it's so how i can remove this signal from my circuit. I think that this is a common mode signal. * I need to know how can i select the value of my fuse instaled on the primary side of 220 VAC transformer. I have a board with transformer of 12 VA and 220 VAC input and it uses a fuse 3.15 A how the designer of this board select this fuse. Waiting your reply With my best regards Yasser El-haddad
