DIFF Subgroup
H01G 7/028 Full Title
Capacitors in which the capacitance is varied by non-mechanical means; Processes of their manufacture > Electrets, i.e. having a permanently-polarised dielectric
H01G 7/028 Capacitors in which the capacitance is varied by non-mechanical means; Processes of their manufacture > Electrets, i.e. having a permanently-polarised dielectric