electronic circuits 236 history 40 radiocommunications 35 aerials 30 low-frequency amplifiers 30 radio receivers 30 audiovisual equipment 28 more ... radio transmitters 20 electronic regulators 15 amplifiers 14 power amplifiers 13 military history 12 electronic security devices 12 switches 11 power supplies 10 loudspeakers 10 accumulator batteries 9 electronics 9 accumulator charging 9 osobnosti 8 lighting engineering 8 wireless broadcasting 7 timers 7 impedance 6 optical signal receivers 6 breakers 6 optical signal transmitters 6 microphones 5 reproduction appliances 5 buses (computer science) 5 less ...