nber category 4 Electrical & Electronic subcat 41 Electrical Devices

uspto classes
174 Electricity: Conductors and Insulators
200 Electricity: Circuit Makers and Breakers
327 Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems
329 Demodulators
330 Amplifiers
331 Oscillators
332 Modulators
334 Tuners
335 Electricity: Magnetically Operated Switches, Magnets, and Electromagnets
336 Inductor Devices
337 Electricity: Electrothermally or Thermally Actuated Switches
338 Electrical Resistors
392 Electric Resistance Heating Devices
439 Electrical Connectors

Historic patent counts for subcat 41

uspto search in the 1790 to present database

ccl/174/$ OR ccl/200/$ OR ccl/327/$ OR ccl/329/$ OR ccl/330/$ OR ccl/331/$ OR ccl/332/$ OR ccl/334/$ OR ccl/335/$ OR ccl/336/$ OR ccl/337/$ OR ccl/338/$ OR ccl/392/$ OR ccl/439/$

Back to the NBER List