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Microphone
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Resistance device
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Apparatus for generating electrical potential
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Electrical microphone
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Resistance device
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Method for generating electrical potential
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Method and an apparatus for electrically effecting synthetic reactions
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Apparatus for generating electrical potential
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Sound-emitting device
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Method of making a resistance element
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Microphone
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Resistance device
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Electrical relay
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Gaseous discharge device
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Electrical condenser
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Ionic-discharge device
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Vacuum-tube relay
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Electron-emission element
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Electric discharge display device
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Electric condenser
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