newbie111
Member level 2
if the PIC and the relay share the same power supply
the equation of calculating the resistor for the npn transistor's base
is 0.2 x relay resistance x hfe
but if the pic uses 5v and the relay (separate) uses 12 v
how do i calculate the resistor for the base of the npn transistor
?
Thanks
the equation of calculating the resistor for the npn transistor's base
is 0.2 x relay resistance x hfe
but if the pic uses 5v and the relay (separate) uses 12 v
how do i calculate the resistor for the base of the npn transistor
?
Thanks