1544.
22
(8) Cold cathode tubes, whether gas-filled or not, operating in a manner similar to a spark-gap, containing three or more clcctrodes and having all of the following characteristics-›
(1) Rated for an anode peak voltage of 2,500 volts or mone:
(i) Rated for peak currenty of 100 amps or more:
(iii) An anode delay time of 10 microseconds or less; Gv) An envelope diameter of less than 1 inch (25.4 millimetres)
Semi-conductor diodes and thyristors, except photodiodes (see item 1548), as follows-
(a) Diodes having 3 bulk material other than silicon,
germanium, selenium or copper oxide;
(8) Silicon and germanium diodes (including mixer, detector, frequency-changing and variable capacitance diodes, and diodes used for the direct conversion of DC to RF powed), designed or rated for use at input or output frequencies greater than 300 megaHertz; except
(0) Point-contact diodes designed for LIS al input frequencies pot exceeding | gigaHertz:
(ii) Voltage-variable capacitance diodes designed for tuning and automalic frequency control in entertainment- type television and radio receivers, having all of the following characteristics—
(1) a rated power dissipation of less than 0.5 watt at
25°C;
(2) a series inductance higher than 3 nanoHenries;
(3) a typical figure of merit Q of less than 200 measured at a reverse voltage of 4 volts and a frequency of 50 mega Hertz:
(e) Silicon and germanium diodes having a rated maximum
reverse recovery time of less than 30 nanoseconds;
(4) Tunnel diodes;
1546.
1548.
1549.
(e) Thyristors having a rated turn-off time of less than 10
micraseconds.
1550.
1545.
Transistors and specialized parts therefor, except photo- transistors (see item 1548), as follows-
(a) of any type using any semi-conductor material having 4 or more aclive junctions within any single block of semi- conductor material:
1553.
(5)
Of any type using a bulk semi-conductor material other than germanium or silicon:
(c) Using germanium as the bulk semi-conductor material and
having any of the following characteristics—
(i) An average IT of 40 to 240 megaHertz and designed to have a maximum collector dissipation greater than 150 milliwatts;
(i) An average FT greater than 240 mega Hertz,
1555.
23
(4) Using silicon as the bulk semi-conductor material and
having any of the following characteristics—
() An average IT of up to 500 kiloHertz and designed to bave a maximum collector dissipation greater than $
watts:
(ii) An average FT from over 300 kiloHertz to megaHertz and designed to have a maximum collector dissipation greater than 500 milliwatts:
(ü) An average fT from over 3 megaHertz to 20 megahertz and designed to have a maximum collector dissipation greater than 250 milliwatte;
(iv) An average fT greuler than 20 megaHertz;
(v) Majority carrier devices, including but not limited to field effect transistors and metal oxide semi-conductar transistors;
(vi) A modulus of the current gain in the common emitter configuration of 10 or more for collector currents of 100 microamperes or less.
Dendritic produced forms of any semi-conductor material, or combinations thereof, suitable for use in diodes or transistors.
Photo cells, as follows-
(a) Photoelectric cells, photo-conductive celts (including photo- transistors and similar cells) with a peak sensitivity at a wavelength longer than 12,000 Angstrom units or shorter than 3,000 Angstrom units;
(2) Photo-transistors (photo-conductive cells including photo- diodes) with a response time constant of I millisecond or less measured at the operating temperature of the cell for which the time constant reaches a minimum.
Photomultiplier tubes as follows-
(a) For which the maximum sensitivity occurs at wavelengths longer than 7,500 Angstrom units or sharict than 3,000 Angstrom units; or
(6) Having an anode pulse rise time of less than t nanosecond.
Thermal detecting cells, ie bolometers and thermocoupled detectors, radiant energy types only, with a response time constant of less than 10 milliseconds measured at the operating temperature of the cell for which the time constant reachea a minimum.
Flash-discharge type X-ray systems, including tubes, except Chase systems or tubes having all of the following specifica- tions-
(a) Peak power of 500 megawatts or less, (b) Output voltage of 500 kilovolts or less; (c) Pulse width of 0.2 microsecond or more.
Image intensiflers, image converters and specialized com- poncats, electronic storage tubes including memory transformers of radar pictures, and ruggedized vidicon-type tubes (except