Top IPC subclasses
1
|
G01R
|
15
|
Measuring electric variables; measuring magnetic variables
|
2
|
H03H
|
4
|
impedance networks, e.g. resonant circuitsresonators
|
3
|
H03B
|
1
|
generation of oscillations, directly or by frequency-changing, by circuits employing active elements
|