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Gate switch
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Heat detector for aircraft
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Photocell mounting device
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High vacuum system with recirculating conduit
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Radiation detector
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Fire warning device
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Movie projector safety device
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Electronic timing device
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Photoelectric relay
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Movie projector safety switch
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Electronic timing device
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Thermal microswitch
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Electrical control
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Conductivity control
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System of light modulation
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Electron discharge device
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GB597885A
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Improvement in electronic control apparatus
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Control system with gas discharge tube
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GB589300A
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Improvements in photoelectric control
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Electric detection apparatus
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