Guard-ring diode apparatus by Unilab, incorporating Ferranti GRD7 thermionic valve; for measuring the charge-to-mass ratio of the electron by the magnetron method, and other experiments. (Without solenoid or cylindrical magnet Guard-ring diode apparatus by Unilab 1970-1979
367 CV2154 crystal diodes - silicon SIM5 and germanium GEM5 used in civil marine radar application. 1950 - 1980 diodes CV2154 1950-1980