{"type_number":"80","canonical_url":"https://tubeofile.com/tubes/80","manufacturer":null,"tube_type_key":"rectifier","tube_type_display_name":"Rectifier","base_name":"UX4","description":"Full-wave high-vacuum rectifier with directly heated (filament) cathode. Introduced in the late 1920s as one of the earliest widely-used power rectifiers for AC-operated radio receivers. Uses a 4-pin UX4 base. Ratings and characteristics are identical to octal types 5Y3GT and 5Y4G.","is_directly_heated":true,"completeness":"high","notes":["Directly heated (filament cathode) — observe heater warm-up time before applying B+ to protect the tube and filter capacitors.","Maximum steady-state peak plate current per plate is 400 mA. Maximum transient peak plate current is 2.2 A per plate.","Voltage drop of 60 V at 125 mA DC per plate, providing natural current-limiting 'soft start' characteristics.","Input condenser (capacitor-input filter): limited to 10 µF maximum per the datasheet.","The rating chart shows operating regions for capacitor-input and choke-input filter configurations at various RMS supply voltages.","One of the most widely-used rectifiers of the pre-war era; found in virtually every AC-operated radio receiver of the 1930s."],"references":["https://frank.pocnet.net/sheets/127/8/80.pdf"],"source_urls":{"r_type":null,"tdsl":"http://tdsl.duncanamps.com/show.php?des=80","radiomuseum":"https://www.radiomuseum.org/tubes/tube_80.html"},"raw_equivalents":["CV617","VT-80","1821","3841"],"equivalents":[],"similar":[{"type_number":"5Y3GT","reason":"Octal-based equivalent with identical ratings and characteristics — not pin-for-pin compatible due to different base (UX4 vs Octal)","has_detail_page":false},{"type_number":"5Y4G","reason":"Octal-based equivalent with identical ratings and characteristics but different pinout — not pin-for-pin compatible","has_detail_page":true},{"type_number":"5Z3","reason":"Same UX4 base but higher current rating (225 mA vs 125 mA) and higher filament current (3.0 A vs 2.0 A)","has_detail_page":true},{"type_number":"83","reason":"Same UX4 base, mercury-vapour rectifier — much lower voltage drop but requires controlled warm-up sequence and has limited life","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Anode 1 (Plate 1)","function_code":"a1","notes":null},{"pin_number":"2","function":"Filament","function_code":"h","notes":null},{"pin_number":"3","function":"Anode 2 (Plate 2)","function_code":"a2","notes":null},{"pin_number":"4","function":"Filament","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"5.0","numeric_value":"5","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"2.0","numeric_value":"2","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Rectifier","tube_type_key":"rectifier","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"350","numeric_value":"350","unit":"V","param_group":"absolute_max"},{"key":"PIV","display_name":"Peak Inverse Voltage","value":"1400","numeric_value":"1400","unit":"V","param_group":"rectifier"},{"key":"Vdrop","display_name":"Voltage Drop (typical)","value":"60","numeric_value":"60","unit":"V","param_group":"rectifier"},{"key":"C_max","display_name":"Max C-input Filter Capacitor","value":"10","numeric_value":"10","unit":"µF","param_group":"rectifier"},{"key":"Ia_peak","display_name":"Peak Anode Current (surge)","value":"400","numeric_value":"400","unit":"mA","param_group":"rectifier"},{"key":"Idc_max","display_name":"Max DC Output Current (total, not per-anode)","value":"125","numeric_value":"125","unit":"mA","param_group":"rectifier"}]}],"synced_at":"2026-04-08T07:53:38.908Z"}