Quality of elements, reliability, cut-off frequency, production margins, standard value series. Manufacturability, repeatability, prindted circuit boards, cooling. Thermoelectricity, thermoelement, Peltier element, thermostat, electronic thermometer (diode thermometer), thermistor, pyrometer. Electrodynamics, environment impedance transformation, loudspeaker, resonators. CRT, thermoemission, videoamplifiers, deflection, luminophores. El. safety, leakage currents, safety classes, internal resistence, circuit breakers. Power supplies, transformers, voltage doublers, voltage multiplier, switch-mode power supply, efficiency, EMC. Interference, coupling, grounding, electrical and magnetic fields attenuation, humidity, photosensitivity, microphony.