Amplifiers; Antennas; Connections for electric lines; Contacts, electric; Electric resistances; Electrical inductors; Electromagnetic coils; Galvanometers; Light emitting diodes (LEDs); Luminous pointers; Magnetic tape drives; Magnetizers; Radios; Relays, electric; Resistances, electric; Semi-conductors; Semiconductor devices; Switches, electric; Transducers that utilize ultrasonic oscillations to test for stress and fatigue in metal and metal structures; Transistors; Transmitters of electron...