Synonyms to focus tube

amplifier, attenuator, audio-frequency tube, ballast regulator, ballast tube, beam-switching tube, convertor, current regulator, damper, detector, discriminator, doubler, ear trumpet, electronic hearing aid, generator, hard-of-hearing aid, hearing aid, iconoscope, inverter, limiter, local-oscillator tube, megaphone, mixer tube, modulator, multiplier, multipurpose tube, multivibrator, oscillator, output tube, phase inverter, picture tube, power tube, preamp, preamplifier, pulse generator, radio-frequency tube, receiving tube, rectifier tube, regulator, repeater, speaking trumpet, stethoscope, transducer, transistor hearing aid, trigger tube, vacuum-tube hearing aid, AC motor, Corliss engine, Otto engine, PCV valve, Wankel engine, accelerator, actuator, aeromotor, agent, air engine, alternator, ammeter, ancestors, anode, apprentice, architect, armature, artificer, artist, author, autoconverter, autostarter, autotransformer, battery charger, beam engine, bearings, begett